Malt Profiling with SIFT-MS

Volume 28 Number 5 May 2010www.chromatographyonline.com

Malt Profiling with SIFT-MS

Pittcon 2010 GC Systems and Accessories Review

Pittcon 2010 HPLC Systems and Accessories Review

Scrutinizing Your Methods Too Much?

332 LCGC NORTH AMERICA VOLUME 28 NUMBER 5 MAY 2010 www.chromatographyonline.com

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www.chromatographyonline.com

Volume 28 Number 5 May 2010

Volume 28 Number 5 May 2010www.chromatographyonline.com

Malt Profiling with SIFT-MS

Pittcon 2010 GC Systems and Accessories Review

Pittcon 2010 HPLC Systems and Accessories Review

Scrutinizing Your Methods Too Much?

®

LCGC North America (ISSN 1527-5949 print) (ISSN 1939-1889 digital) is published monthly except for two issues in August by Advanstar Communications Inc., 131 West First Street, Duluth, MN 55802-2065, and is distributed free of charge to users and specifiers of chromatographic equipment in the United States and Canada. Single copies (prepaid only, including postage and handling): $15.50 in the United States, $17.50 in all other countries; back issues: $23 in the United States, $27 in all other countries. LCGC is available on a paid subscription basis to nonqualified readers in the United States and its possessions at the rate of: 1 year (13 issues), $74.95; 2 years (26 issues), $134.50; in Canada and Mexico: 1 year (13 issues), $95; 2 years (26 issues), $150; in all other countries: 1 year (13 issues), $140; 2 years (26 issues), $250. Periodicals postage paid at Duluth, MN 55806 and at additional mailing offices. POSTMASTER: Please send address changes to LCGC, P.O. Box 6168, Duluth, MN 55806-6168. Canadian GST number: R-124213133RT001, Publications Mail Agreement Number 40017597. Printed in the USA.

Contents

Cover photos

by Joe Zugcic.

Product featured on cover

supplied by MicroLiter Analytical

Supplies, Inc. (Suwanee, Georgia) and

PerkinElmer (Shelton, Connecticut).

Cover design: Julie Silbernagel.

DEPARTMENTS

340 From the Editor

342 Peaks of Interest

396 Products

400 Literature

401 Classified Directory

402 Ad Index

364

344

358

COLUMN WATCH

A Review of Column Developments forSupercritical Fluid ChromatographyTerry Berger and Blair BergerThe authors review the requirements for columns specifically designed and manufactured for SFC.

LC TROUBLESHOOTING

Too Much ScrutinyJohn W. DolanIn recent conversations at Pittcon 2010, it became clear to the author that sometimes we get too focused on the details of the method without backing up and determining how they fit into the big picture.

GC CONNECTIONS

New Gas Chromatography Products at Pittcon 2010John V. HinshawJohn Hinshaw presents his annual review of all that was new in the field of gas chromatography at Pittcon 2010.

INNOVATIONS IN HPLC

HPLC Systems and Components Introduced at Pittcon 2010: A Brief ReviewMichael SwartzMichael Swartz presents his first annual review of HPLC systems and accessories at Pittcon 2010.

386 Real-Time Profiling of Volatile Malt Aldehydes Using Selected Ion Flow Tube Mass Spectrometry Jessika De Clippeleer, Filip Van Opstaele, Joeri Vercammen, Gregory J. Francis, Luc De Cooman, and Guido AertsThe authors use headspace SIFT-MS to target and identify volatiles in various malt aldehydes. The specificity and speed are compared to current methodology.

376


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336 LCGC NORTH AMERICA VOLUME 28 NUMBER 5 MAY 2010


Kevin D. Altria GlaxoSmithKline, Ware, United Kingdom

Daniel W. Armstrong University of Texas, Arlington

Michael P. Balogh Waters Corp., Milford, Massachusetts

Brian A. Bidlingmeyer Agilent Technologies, Wilmington, Delaware

Dennis D. Blevins Agilent Technologies, Wilmington, Delaware

Phyllis R. Brown Department of Chemistry, University of Rhode Island, Kingston, Rhode Island (ret.)

Peter Carr Department of Chemistry, University of Minnesota, Minneapolis, Minnesota

Jean-Pierre Chervet Antec Leyden, Zoeterwoude, The Netherlands

Nelson Cooke Consultant, Hercules, California

John W. Dolan LC Resources, Walnut Creek, California

Roy Eksteen Tosoh Bioscience LLC, Montgomeryville, Pennsylvania

Fritz Erni Novartis Pharmanalytica SA, Locarno, Switzerland

Leslie S. Ettre Department of Chemical Engineering, Yale University, New Haven, Connecticut

Anthony F. Fell School of Pharmacy, University of Bradford, Bradford, United Kingdom

Francesco Gasparrini Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università “La Sapienza,” Rome, Italy

Joseph L. Glajch Bristol-Meyers-Squibb Medical Imaging, North Billerica, Massachusetts

Richard Hartwick PharmAssist Analytical Laboratory, Inc., South New Berlin, New York

Milton T.W. Hearn Center for Bioprocess Technology, Monash University, Clayton, Victoria, Australia

John V. Hinshaw Serveron Corp., Hillsboro, Oregon

John S. Hobbs Consultant

Kiyokatsu Jinno School of Materials Science, Toyohashi University of Technology, Toyohashi, Japan

Wolfgang Lindner Institute of Analytical Chemistry, University of Vienna, Vienna, Austria

Ira S. Krull Northeastern University, Boston, Massachusetts

Ronald E. Majors Agilent Technologies, Wilmington, Delaware

Karin E. Markides Uppsala University, Uppsala, Sweden

R.D. McDowall McDowall Consulting, Bromley, United Kingdom

Michael D. McGinley Phenomenex, Inc., Torrance, California

Victoria A. McGuffin Department of Chemistry, Michigan State University, East Lansing, Michigan

Mary Ellen McNally E.I. du Pont de Nemours & Co., Wilmington, Delaware

Imre Molnár Molnar Research Institute, Berlin, Germany

Glenn I. Ouchi Brego Research, San Jose, California

Colin Poole Department of Chemistry, Wayne State University, Detroit, Michigan

Fred E. Regnier Department of Chemistry, Purdue University, West Lafayette, Indiana

Pat Sandra Research Institute for Chromatography, Kortrijk, Belgium

Peter Schoenmakers Department of Chemical Engineering, University of Amsterdam, Amsterdam, The Netherlands

Lloyd R. Snyder LC, Resources Walnut Creek, California (ret.)

Michael E. Swartz Synomics Pharmaceutical Services, Wareham, Massachusetts

Klaus K. Unger Institute for Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University, Mainz, Germany

Thomas Wheat Waters Corp., Milford, Massachusetts

CONSULTING EDITORS: Jason Anspach, Phenomenex, Inc., Stuart Cram, ThermoFisher Scientific, David Henderson, Trinity College; Tom Jupille, Rheodyne LLC; Sam Margolis, The National Institute of Standards and Technology; Joy R. Miksic, Bioanalytical Solutions LLC; Frank Yang, Micro-Tech Scientific.

Editorial Advisory Board


David Walsh

Editor-in-Chief

[email protected]

FROM the EDITOR

M any readers who also subscribe to LCGC’s sister publication, Spectroscopy, may have read industry expert Bob McDowall’s November 2009 column on the new posture of the U.S. FDA (“The Tiger Has Sharp New Teeth,” Spectroscopy 24[11], 23–29

[2009]). As he saw it, “The new FDA Commissioner wants a strong FDA and is backing her words with action.” In light of the news coming out of Washington at the time of this writ-ing, he may have been more correct than he imagined. Here we are just a few months later, and the internet, cable news networks, and radio talk shows are all abuzz with the latest initiative put in place by the FDA and its commissioner, Dr. Margaret Hamburg, to limit the amount of sodium Americans consume.

According to the Washington Post (4/20/10), “The effort would eventually lead to the first legal limits on the amount of salt allowed in processed foods,” and would also lead to an unprecedented show of power on the part of not only the FDA, but the federal government in general. And while the left may cheer such a move as protecting public health and liber-tarians and the right may express shock at such a chilling invasion of personal freedoms, one is left to wonder what the implications of such a posture on the part of the FDA may be for the separations community in particular and laboratories in general.

At the very least, it seems to indicate that regulations such as the postinspection response program described by McDowall (initiated on September 15, 2009) will be the norm rather than the exception. And new requirements such as complete responses to 483 observations within 15 working days could be a harbinger of further regulations to come for laboratories in the U.S., rather than a one-time move.

It will be interesting to see how this initiative plays out in the realm of public opinion, where the FDA will either be emboldened to pass further regulations and restrictions (sharp-ening the tiger’s teeth further) or chastened by public outcry. One thing is certain, we will all be hearing more on this in the weeks and months to come.

The FDA’s Teeth Get Sharper


PEAKS of Interest

Phenomenex Launches Chiral

Screening Service

Phenomenex (Torrance, California)

has announced the launch of its Chiral

Screening Service for customers in

pharmaceutical and natural products

research and development.

According to the company, the free

service provides target screening using

a library of HPLC and SFC columns

including polysaccharide-based offer-

ings, which demonstrate a success rate

approaching 90%. After resolving the

chiral compound, Phenomenex also

reportedly produces method develop-

ment and optimization for the service

customer within 10 business days.

“Resolving chiral compounds is rela-

tively difficult, and column selection can

be complicated,” explained Kari Carlson,

brand manager for Phenomenex. “Our

Chiral Screening Service eliminates time-

consuming guesswork and also gives

customers a chance to ‘test-drive’ our...

columns.”

Dionex Receives Polish IC order

Dionex Corporation (Sunnyvale, Califor-

nia) has announced that the company

is to supply 42 ion chromatography

systems to the Polish Environmental

Inspectorate, one of the largest users

of ion chromatography in Poland. The

systems will be used in environmental

labs throughout Poland for the analysis

of inorganic anions in water and air

samples.

The order was won by AGA Analyti-

cal, the company’s distributor for IC and

solvent extraction products in Poland.

According to the company, the main

technical advantages of the systems

include the use of 2-mm microbore

columns, self-regenerating membrane

suppressors, and several key data system

features.

Linde Gases Receives Chinese

Certification for Calibration

Gas Supply

Linde Gases (Munich, Germany) has

been granted GBW certification by

the Chinese State Bureau of Quality

and Technical Supervision,

Chromatography Market Profile

Chinese Separation Market

The rapid expansion in

China continues to fuel

growth for separation

science technologies.

This market includes

technologies such as

HPLC,GC, ion chromatog-

raphy, low-pressure LC,

flash chromatography,

thin-layer chromatogra-

phy, chemical sensing,

capillary electrophoresis, and discrete and continuous flow analyzers. All

separations instruments incorporate the following: a sample-introduc-

tion port of some type; a delivery system for a mobile phase carrier that

moves the sample through the system; a stationary phase, which can be

held within a column; a capillary; and one or more detectors that identify

changes in the nature or amount of the material emerging from the col-

umn. The different types of mobile phases: liquid, gas, supercritical fluid,

etc., contribute to the names of the techniques.

HPLC and GC are the largest markets in China, with HPLC being one of the

fastest growing, driven by the pharmaceutical industry, the public sector, and

food analysis. GC’s growth is driven by the oil and gas industry, in addition to

food and agriculture.

Chinese pharmaceutical laboratories are by far the largest consumers of

separation technology, accounting for nearly a quarter of the region’s separa-

tion demand. Academia is the second largest segment, representing 13% of

the market. The growth in academia is stimulated by increased government

outlays for education and university construction. The food and agriculture

and oil and gas industries are tied for the third and fourth spots, each with

about 12% of the region’s separation demand. Government testing is in fifth

place with 8% of the market share.

The foregoing data were extracted and adapted from SDi’s Market Analy-

sis and Perspective report entitled China: Analytical Instrument Demand &

Production. For more information, contact Glenn Cudiamat, VP of Research

Services, Strategic Directions International, Inc., 6242 Westchester Parkway,

Suite 100, Los Angeles, CA 90045, (310) 641-4982, fax: (310) 641-8851, e-mail:

[email protected].

approving the company’s production

of gas reference materials from its

plant in Suzhou, Jiangsu province in

eastern China.

GBW is the official Chinese quality

standards institute and their accredita-

tion is a requirement for gas produc-

tion facilities wishing to supply special-

ity calibration gas mixtures to both

domestic and foreign-owned companies

operating in China.

The plant will produce the company’s

high-purity gases and gas mixtures for

the calibration of measurement instru-

mentation for environmental monitor-

ing purposes, including the detection

and control of combustion emissions

for power generation. According to

the company, this will enable them to

better support the growing emphasis

being placed by China on tackling its

CO2 emissions. ◾

Oil and gas12 %

Government testing

8%

Others32%

Pharmaceuticals23%

Academia13%

Agriculture/food/beverage

12%

Chinese separations demand by industry.


COLUMN WATCH

Guest Authors

Terry Berger and Blair Berger

Terry Berger, a pioneer

in supercritical fluid

chromatography

(SFC), reviews the

requirements for columns

specifically designed and

manufactured for SFC.

After an introduction

to the evolution of

SFC instrumentation,

he discusses column

developments, particularly

with regard to speed,

selectivity, and efficiency,

touching on the use of

chemometrics to predict

retention. Finally, a survey

of achiral and chiral

columns for analytical and

semipreparative use rounds

out this update.

A Review of Column Developments for Supercritical Fluid Chromatography

Supercritical fluid chromatography

(SFC) has a convoluted past. On

the instrumentation side, aca-

demic laboratories have found it difficult

to make or buy SFC equipment, resulting

in most development being made by end

users or manufacturers. The history of

column development closely follows the

history of SFC instrumentation. Column

manufacturers have been slow to embrace

SFC. In fact, up until about 2000, there

were few SFC-specific columns. So per-

haps the most important aspect of this

article is the fact that there is actually

something to review. Because this is a

maiden attempt to review the role of

columns for SFC, we first present a very

brief history of commercial SFC instru-

mentation, followed by the closely related

evolution of thought on how to make

SFC columns, and concluding with

what’s available today (and why). There is

no attempt to be comprehensive.

The Evolution of

Instrumentation for SFC

Klesper first demonstrated SFC in 1962

(1), collecting fractions and analyzing

them off-line. Widespread awareness

of SFC only occurred after Hewlett

Packard (HP, now Agilent Technolo-

gies, Santa Clara, California) presented

a series of papers at the 1979 Pittsburgh

Conference and introduced an SFC

modification kit for the model 1084

high performance liquid chromatogra-

phy (HPLC) system, in 1981. This was

a packed-column instrument with inde-

pendent flow, composition, pressure,

and temperature control. Detection

was by UV, but other detection meth-

ods, such as flame ionization detection

(FID) and mass spectrometry (MS) were

sometimes used. Columns of the day

were standard normal-phase columns

borrowed from HPLC. The common

packings were silica, phenyl, cyano,

amino, and diol. Few were endcapped.

Most were 250 mm × 4.6 mm with 5-

μm totally porous silica packings, but

the range of lengths, internal diameters,

and particle sizes available were similar

to today, including a few experimental

sub-2-μm pellicular–nonporous pack-

ings. Elution was isocratic or with com-

position gradients. The fluid of choice

was carbon dioxide, modified with an

organic solvent. The back-pressure regu-

lator was a slightly modified mechanical

type, but a few were further modified

with a chain drive and a stepper motor

for pressure programming. When the

SFC-incompatible HP model 1090

HPLC system was introduced, the HP

model 1084 was withdrawn from the

market, ending production of the first

commercial SFC system.

Preparative SFC had a beginning in

the early 1980s with Perrut patenting

recycle preparative SFC with cyclone sep-

arators, for petroleum applications, using

pure carbon dioxide as the mobile phase,

in 1982 (2). Manufacturers Prochrom

[now part of Novasep (Pompey, France)]

and Novasep have had a continuous pres-

ence in larger scale SFC since that time.

Jasco (Easton, Maryland) introduced

their combined supercritical fluid extrac-

tion (SFE)–SFC system in 1985, which

was similar to the modified HP1084 sys-

tem. It featured the first electronic back

pressure regulator specifically designed

for SFC (and SFE).

Capillary or open-tubular SFC, origi-

nally reported by Milton Lee and oth-

ers in 1984 (3), was commercialized by Ronald E. MajorsColumn Watch Editor


1986, through Lee Scientific (acquired

by Dionex Corporation, Sunnyvale, Cali-

fornia) but spun off. Core individuals

are now part of Selerity (Salt Lake City,

Utah). Capillary columns dominated the

development of both theory and instru-

mentation in SFC for the next 5–7 years.

Capillary instruments closely resembled

a GC, but used a syringe pump as a pres-

sure source, and a fixed restrictor to limit

flow through small-internal-diameter

open-tubular columns. The vast majority

of applications used pressure program-

ming with pure carbon dioxide as the

mobile phase. Detection was FID but

many other detectors were used, includ-

ing MS. Columns were mostly 50-μm

i.d. fused silica.

Through the late 1980s, numerous

other companies (including Isco [Lincoln,

Nebraska], Carlo Erba [Milan, Italy], and

CDS [Avondale, Pennsylvania]) intro-

duced similar equipment (syringe pumps,

pressure programming, fixed restrictors,

and FID systems), but they were limited

by a U.S. patent to only using micro-

packed columns. Most have exited the

business and some are no longer in busi-

ness or have been absorbed by others.

In 1992, Gilson and HP both intro-

duced commercial analytical-scale SFC

systems. For HP, this was their second

product entry. Their hardware used

binary, reciprocating pumps, electronic

back pressure regulators, UV detectors,

and computer control of all variables.

The HP system was capable of both

packed and capillary column operation.

The Gilson pumps delivered a higher

flow rate, prompting several largely

unsuccessful attempts to create a small

scale semipreparative instrument, using

1-cm columns. Gilson exited the SFC

business around 2002. The HP product

line was sold to Berger Instruments (BI)

in 1995. BI immediately dropped capil-

lary operation.

Semipreparative SFC took off after BI

introduced the semipreparative AutoPrep

system for achiral library purification

and the MultiGram II system for chiral-

like stacked injections. These were basi-

cally scaled up versions of the analytical

hardware, with a new kind of phase sepa-

rator. Columns were 2–3 cm i.d., with

packings identical to analytical columns.

BI was acquired by Mettler Toledo in

2000, who sold the business to Thar

(2007), who were acquired by Waters

(Milford, Massachusetts) (2009). Agilent

Technologies is reentering the business

(2010), working with Aurora SFC Sys-

tems (Sunnyvale, California), to convert

certain HPLC systems into SFC systems

with minimal modification. Thus, for

the first time, the two main suppliers of

HPLC equipment (Waters and Agilent)

are both involved in SFC.

Column Development

The turbulence in SFC hardware devel-

opment during the 1980s through the

1990s can be directly attributed to an

unfortunate elutropic series published by

Calvin Giddings (4 ). Giddings estimated

that dense carbon dioxide was similar

to isopropanol in solvent strength. This

implied that density programming of

pure carbon dioxide would have the same

effect as a composition program from

pure hexane to pure isopropanol. This

would have been hugely important, as

controlling a physical parameter, such as

pressure, is far easier and less expensive

than controlling flow and composition.

It also would allow the use of FID. With

the benefit of hindsight, we must say this

eluotropic series is completely wrong.

The Giddings series was never challenged

publicly and was never corrected. No one

would suggest using pure hexane to sepa-

rate polar drugs, yet (we now know that)

pure carbon dioxide, a very nonpolar

substance, similar to a hydrocarbon, was

presumed to elute such compounds.

Low-to-moderately polar compounds

such as benzoic acid and aniline could be

eluted from capillary columns with pure

carbon dioxide, whereas they exhibit

much more retention, tailed severely, or

could not be eluted from packed columns

under the same conditions. The elution

from capillaries was thought to confirm a

high solvent strength for the pure carbon

dioxide. The poor performance by the

packed columns was widely attributed

to “active sites” on the columns. Capil-

lary columns have a much lower phase

ratio than packed columns and typically

are coated with less polar phases. Each

characteristic makes capillaries much less

retentive than packed columns, but these

facts were largely ignored.

Several reviews (5,6) of packed col-

umns for SFC, written in 1990, indicate a

near obsession with the use of pure fluids,

pressure programming, and FID. It was

still widely thought that modifiers only

covered active sites on the support, and

did not increase solvent strength dramati-

cally, or improve the solubility of polar

solutes. These can be summarized by the

following statement: “Therefore, station-

ary phases for SFC are desirable which

allow the elution of the largest possible

variety of solutes as sharp, symmetrical

peaks, using pure carbon dioxide . . .” (6).

Thus, creating a more inert support was

thought to be the way forward.

Polymer-coated particles such as Del-

tabond (Keystone Scientific, now part of

Thermo Fisher Scientific, Madison, Wis-

consin) allowed the elution of somewhat

more polar molecules and somewhat

improved peak shapes, but the degree

of improvement was still limited, often

producing tailing peaks. Several poly-

mer-based particles were also developed,

without silica. These tended to allow

the elution of slightly polar compounds

(aniline, benzoic acid), without additives,

but efficiency was very poor. Unfortu-

nately, these modest improvements fur-

ther encouraged the use of pure carbon

dioxide, with more polar solutes, while

increasing the resistance to the more

complex and expensive use of binary

pumping systems, and UV detectors with

packed columns.

Throughout the 1980s and into

the 1990s, a relatively small number of

laboratories continued to use modified

HPLC systems with binary pumping

systems, composition programming, and

UV detection. The use of additives was

pioneered in the very late 1980s (7–11),

which dramatically increased the polarity

of compounds that could be separated by

SFC (12–16). Many classes of polar solutes

including phenols, polyhydroxy, hydroxy-

acids, polyacids, aliphatic amines, and

many drug families were only separated

using additives like citric acid, trifluoro-

acetic acid, isopropylamine, triethylamine,

ammonium acetate, and many others.

By 2000, it was acknowledged that

capillary SFC had been oversold (17) espe-

cially for the elution of polar solutes. Nev-

ertheless it was still stated that: “Although

the future will undoubtedly see continued

greater use of packed column than open-

tubular column SFC, the two techniques

should be seen as complementary rather

than competitive methods.”


It also was stated that packed column

SFC was a “suitable replacement for

normal-phase liquid chromatography.”

This simple statement fails to convey the

tremendous advantages SFC has versus

normal-phase HPLC. Normal-phase

LC mobile phases are largely limited to

nonpolar (such as hexane and isooctane)

and highly flammable organic mixtures.

Traces of water in the mobile phase

caused significant shifts in retention

times. Reequilibration times are very

long. Solute binary diffusion coefficients

are significantly lower than in modified

carbon dioxide, making the chroma-

tography much slower. Viscosity of the

fluids is higher, leading to larger pressure

drops. SFC is much faster, reequilibrates

extremely fast, allows steep gradients, is

tolerant of significant amounts of water,

allows very long columns, or very small

particles with modest pressure drops, is

not flammable, and is “green.” In our

opinion, SFC outperforms normal-phase

HPLC and even reversed-phase HPLC.

Before 2000, there had been few

columns sold only as SFC columns.

An example is the hydrocarbon group

separation columns used to measure aro-

matics in diesel and olefins in gasoline.

These were nothing more than conven-

tional bare silica columns with low met-

als content (Type B silica), sometimes

used with a silver-loaded stationary phase

or an amino phase to further separate the

olefins from the saturates.

Commercial column manufacturers

tended to ignore SFC until the market

grew large enough to justify an invest-

ment. Consequently, by 2000 most of the

available polar stationary phases were the

same as those used more than 20 years

earlier in normal-phase HPLC, with little

improvement. Also, they did not provide

a large variation in selectivity.

By the end of 2000, there was a gen-

eral perception that SFC could separate

a large percentage of small drug-like

molecules, but that additives were

generally necessary. In fact, additives

were used so ubiquitously that often

they were included in the mobile phase

(8,18), even when they weren’t necessary

(19)! Additives continue to be viewed as

undesirable, particularly when a mass

spectrometer is used as the detector. In

one instance, an isopropylamine additive

reacted with a ketone solute. On the other

hand, another ketone solute appeared to

react with an amino stationary phase in

the absence of an additive. In spite of this,

SFC has been moving vigorously into

routine achiral analysis (20–23).

Particle Size and Speed in SFC

In the early 1980s, much of the work

published by Dennis Gere (24) used 3-

μm particles. Amazingly, there has been a

0.3 min

0.6 min

1.5 min

4 min

1

2

3

4

5

(d)

(c)

(b)

(a)A

bso

rba

nce

(m

AU

)A

bso

rba

nce

(m

AU

)A

bso

rba

nce

(m

AU

)A

bso

rba

nce

(m

AU

)

Time (min)

Time (min)

Time (min)

Time (min)

80

60

40

20

0

0 2 4

120

100

80

60

40

20

0

-20

0.5 1 1.5

100

80

60

40

20

-20

0

0.2 0.4 0.6 0.8

200

150

100

50

0.1 0.2 0.3

Figure 1: Isocratic separation of a test mix on (a) 250 mm X 4.6 mm, 5-µm; (b) 150 mm X 4.6 mm, 3.5-µm; (c) 50 mm X 4.6 mm, 3.5-µm; and (d) 50 mm X 4.6 mm, 1.8-µm Zorbax RX-Sil columns (Agilent). Flow rates: 2, 3, and 5 mL/min 22.5% methanol; temperature: 50 °C; pressure: 150 bar (outlet); cell volume: 1.7 µL; injection volume: 2 µL. Peaks: 1 = Ibuprofen, 2 = fenoprofen, 3 = caffeine, 4 = theophyline, 5 = theobromine. Last peak plate number: (a) 25,630, (b) 8180, (c) 3160, (d) 4350.


subsequent, surprising dearth of publica-

tions using smaller particles in SFC. This

absence is all the more surprising when

considering the recent major emphasis

in HPLC for particles smaller than 2

μm. The diffusion coefficients of solutes

in carbon dioxide are 3–5 times higher

than in HPLC, so SFC should be 3–5

times faster on the same-sized particles.

Perhaps, more importantly, the viscosity

of the fluids is much lower than aqueous

based mobile phases. Consequently, pres-

sure drops are much lower, even with the

higher linear velocities. Thus, SFC on 3

μm particles should be as fast or faster

than HPLC on sub-2-μm particles.

To illustrate the speed potential for

SFC by variation of particle size and

column length, several chromatograms

were prepared, as there were few similar

examples available in the literature. It

often is desirable to transfer a method

from a long column packed with larger

particles to a shorter column with smaller

particles, in order to save analysis time.

For method transfer to be feasible, the

stationary phase must remain consistent

independent of particle size or pressure

drops. Three different particle sizes

of the same base silica and three dif-

ferent column lengths were compared

at the same column internal diameter

and isocratic conditions at 50 °C (see

Figure 1). The outlet pressure was fixed

at 150 bar, and the flow rate was varied

between 2 and 5 mL/min, depending

on particle diameter. Figure 1a shows

the separation of xanthenes and profens

using a 250 mm × 4.6 mm column

packed with 5.0-μm silica. The last peak

exhibited over 25,630 isocratic plates in

about 4 min. Decreasing particle size

and column length (Figure 1b) keeps

the resolution about the same but cuts

the analysis time to 1.5 min, just as in

HPLC. A further reduction in column

length while keeping the particle size the

same (Figure 1c), results in a separation

of about one third of the time but with

a slight loss in resolution and efficiency.

Finally, use of a sub-2-μm particle in an

equivalent length column (Figure 1d)

results in a further reduction in analysis

time (0.3-min) with some further band

broadening due to two causes. First, the

5-mL/min flow rate on the latter chro-

matogram (Figure 1d) was significantly

suboptimum (below the van Deemter

minimum) for a 4.6-mm i.d. column and

was limited by the 5-mL/min capability

of the pump. Second, the model 1100B

diode-array detector had a maximum

data rate of 20 Hz and therefore the

chromatographic efficiency of the faster

columns was compromised by its slower

than required response. The chromato-

grams throughout show very consistent

selectivity, even though the particle

diameter was decreased from 5 μm to

3.5 μm, and then to 1.8 μm.

SFC can accomplish the same or

greater speed compared to UHPLC,

using conventional (400 bar) HPLC

hardware and columns, because the vis-

cosity of the fluids is dramatically lower,

resulting in lower pressure drops.

HILIC SFC Columns

Hydrophilic interaction liquid chroma-

tography (HILIC) is an extension of nor-

mal-phase HPLC to more polar solutes.

It has been around since the 1980s, and

is characterized by a hydrophobic, mostly

organic (low water content) mobile phase

used with a hydrophilic stationary phase

in which ionic additives, like ammonium

acetate, are often used. It is thought that

a thin film of adsorbed water acts as part

of the stationary phase. This is similar

to SFC, in which it has been shown that

polar modifiers and additives preferen-

tially adsorb (25,26) onto polar station-

ary phases to form multiple monolayers.

Surprisingly, the literature contains very

few references (27) to the use of HILIC

columns in SFC.

Superficially Porous Particles

for SFC

Another recent trend in HPLC is the use

of small, solid-core (superficially porous)

particles coated with a thick porous layer

of silica (28–32). These particles generate

higher efficiencies compared to totally

porous silica of the same particle diam-

eter. Guiochon (33) recently proposed a

theory covering efficiency in reversed-

phase HPLC for such particles. There

1

2

3

4

5

Ab

sorb

an

ce (

mA

U)

Time (min)

200

175

150

125

100

175

50

0

0.25 0.5 0.75 1

Figure 2: Chromatogram obtained using a hard-core, thick porous layer packing. The first peak (ibuprofen) exhibits >24,000 plates, 1070 plates/s. The last peak (theobromine) exhibits ≈26,000 plates. Column: 150 mm X 4.6 mm, 2.6-µm Kinetex HILIC 100A (Phenomenex); flow rate: 4.4 mL/min; mobile phase: 40% methanol in carbon dioxide; back pressure: 150 bar; temperature: 50 °C; injection volume: 2 µL; cell volume: 1.7 µL; filter: <0.01 min (20 Hz); pressure drop: 185 bar. Peaks: 1 = Ibuprofen, 2 = ketoprofen, 3 = caffeine, 4 = theophyline, 5 = theobromine.


appears to be no reference in the litera-

ture available to the author, in which

such columns have been used in SFC.

However, HILIC versions are available

commercially. The chromatogram in Fig-

ure 2 was generated using a Phenomenex

Kinetex HILIC column packed with a

2.6-μm superficially porous particle and

dimensions of 150 mm × 4.6 mm. In

this chromatogram, up to 26,000 plates

and nearly 1100 plates/s were generated.

In a somewhat slower chromatogram, up

to 50,000 apparent plates were gener-

ated in isocratic runs. The reduced plate

height was as low as 1.3. These somewhat

anecdotal results suggest there is a very

exciting path forward in SFC, and the

author hopes others will publish more

using such columns.

Long Columns for High

Resolution SFC

Another subtle trend in SFC is in the

use of longer columns. In the late 1980s

there were competing theories (34–38)

as to why pressure drops along the axis

of packed columns caused excessive loss

of efficiency. In fact, it was stated (36)

that packed columns could not generate

more than approximately 20,000 plates.

This perception was overturned when

Berger (39) generated 220,000 plates

on a 2.2-m-long column packed with

5-μm particles, with a column hold up

time (void time) of 12 min. In some cir-

cumstances, the only effective means of

resolving complex mixtures or difficult

to separate pairs is simply the brute force

approach of increasing the number of

plates by increasing column length. The

low viscosity and high diffusivity allows

the use of longer columns with modest

pressure drops.

Kot (40), and Phinney (41) extended

the concept by connecting a series of as

many as five different chiral phases in

series, to create a pseudo-universal chiral

column, or combine achiral and chiral

columns to adjust selectivity in mixtures.

Recently, the concept was revived

when five 25-cm-long cyano columns

were connected in series to provide a

high-resolution separation in complex

pharmaceutical analysis (42). The col-

umn stack produced approximately

100,000 plates and was used with com-

position gradients.

Chemometrics and Phase

Selectivity

With the recent rapid growth of SFC,

there has been an explosion of interest in

various chemometric approaches to pre-

dict retention, although the first attempts

date back to the early 1990s (43). Les-

sellier and West have been particularly

active (44–48). In recent work (49), they

presented a graphical comparison of the

selectivity of a large number of differ-

ent stationary phases along five axes,

each representing a different solvation

parameter, as shown in Figure 3. Not too

surprisingly, almost all the traditional

phases (amino, cyano, diol, and silica) are

bunched together, showing mostly strong

hydrogen bond acidity interactions. Per-

haps slightly surprisingly, ethyl pyridine

is very similar, located between cyano

and amino. Diol is shown to be slightly

more affected by hydrogen bond donor

basicity than the others.

MAY 2010 LCGC NORTH AMERICA VOLUME 28 NUMBER 5 353www.chromatographyonline.com

Another group (50) used linear solva-

tion energy relationships (LSERs) with

200 test solutes and came to a slightly

different conclusion stating that hydro-

gen bond donor acidity of the solutes

is particularly important for pyridine

and amino columns. Hydrogen bond

donating ability is small for cyano and

pyridine stationary phases (as one might

expect). Hydrogen bond acceptor basicity

of the solutes is particularly important

for diol and amino columns.

Yet another approach (51) correlated

the retention of some sulfonamides with

total dipole moment, molecular surface

area, and the “electronic charge on the

most negatively charged atom.” Above

10%, log k was shown to vary linearly

with % modifier.

Commercial Achiral Analytical-

to Semipreparative-Scale

Columns

Today, the “holy grail” of SFC column

research remains the elution of polar

solutes without the use of very polar

additives, with at least three companies

creating new phases for SFC. In 2001,

Princeton Chromatography (Cranbury,

New Jersey) introduced the 2-ethylpyri-

dine stationary phase bonded on totally

porous silica. This was possibly the first

stationary phase specifically designed for

packed column SFC. Many compounds,

particularly amines, can be eluted with

no additive, although one is still some-

times required.

The introduction of this phase initi-

ated a fairly consistent, progressive devel-

opment of a number of phases both by

Princeton and others with the intent to

decrease tailing and providing alternative

selectivities. This new interest in SFC

column development has involved pri-

marily smaller companies like Princeton

and ES Industries (Berlin, New Jersey),

but Phenomenex (Torrance, California),

one of the larger column manufacturers,

has also created an SFC product line.

A few others make a modest number of

older phases.

Princeton Chromatography also

makes the more traditional amino,

cyano, diol, and silica columns along

with a number of newer phases includ-

ing a high-load diol (Diol HL), 2- and

4-ethylpyridine, pyridine amide, diethyl-

amino (DEAP), propyl acetamide (PA),

and others. Most columns are packed

with 3- or 5-μm particles. Princeton

appears to be unique in using an SFC

instrument to measure the performance

of every column shipped. They also

provide matched sets of analytical and

semipreparative columns using the same

batch of packing material.

ES Industries also sells a complete line

of traditional amino, diol, cyano, and sil-

ica SFC phases, including NO2, DEAP,

and PFP (pentafluorophenyl). Their

newer phases include amino phenyl, ethyl

pyridine, pyridyl amide, “Epic” Nitro,

and FluoroSep Phenyl as SFC columns.

On their website, they talk about separat-

ing amines, alcohols, and acids without

the use of additives on the amino phenyl

phase and amines without amino addi-

tives on ethyl pyridine. They also claim

simplified fraction collection without

amine or trifluoroacetic acid additives

using the pyridyl amide phase. ES


Industries also makes 1.8-μm particles

coated with amino, phenyl, ethyl pyri-

dine, and FluoroSep phenyl.

Phenomenex sells silica, cyano, and

amino traditional phases specifically

designed for SFC, along with several

newer SFC phases including PFP(2)

(pentafluorophenyl) and a HILIC col-

umn all under their Luna brand. They

also sell a Synergi Polar-RP phase, which

is an ether-linked phenyl with additional

hydrophylic endcapping. The company

claims the PFP phase employs hydrogen

bonding, dipole, and aromatic interac-

tions in addition to hydrophobic interac-

tions to dramatically change selectivity

compared to alkyl phases such as C18.

Their hard-core thick porous-layer

particles under the brand Kinetex can

generate efficiencies in very short times

as shown in Figure 2. They also make

sub-2-μm particles for SFC.

Akzo Nobel (Bohus, Sweden) supplies

Kromasil with all the achiral traditional

phases (amino, cyano, diol, phenyl, and

silica) and mentions their use in SFC.

Kromasil has been used extensively in

SFC but mostly as a base silica material

with chemistries applied by others.

Restek (Bellefonte, Pennsylvania) makes

a wide range of appropriate phases such

as amino, cyano, PFP, phenyl, and silica,

but it does not promote them for use in

SFC. Supelco offers a number of phases

through Sigma-Aldrich (St. Louis, Mis-

souri) including amino, cyano, a polar

embedded amide, PFP, phenyl, silica, and

HILIC, but it does not mention their use

in SFC. Thermo Fisher Scientific sells

Hypersil cyano, PFP, phenyl, and a polar

end-capped C18 (aQ), but it does not men-

tion or promote SFC. Grace Davison (Bal-

timore, Maryland) does not mention SFC.

At Pittcon 2010, Waters announced a

line of Viridis SFC columns from analyti-

cal to semipreparative, concentrating on

semipreparative. Initially, a 2-ethylpyridine

phase and silica were introduced in dimen-

sions of 4.6–30 mm i.d. and 50–250 mm

lengths. Agilent’s offerings are limited

to silica, cyano, HILIC, and Poroshell

120/300 superficially porous shell col-

umns. With their entry into the SFC

hardware manufacturing market, both

Waters and Agilent are likely to extend the

number of phases offered in the future.

Commercial Chiral Analytical-

and Semipreparative-Scale

Columns

Chiral method development, enantio-

meric excess determinations, and chiral

semipreparative separations have been

the strongest applications of SFC, hav-

ing significantly penetrated every major

pharmaceutical company (52–56). A

review of applications through 2008 is

available (57).

The discussion of chiral stationary

phases (CSPs) will be brief, as most of

what is new is also discussed in HPLC.

The phases based upon macrocrystalline

cellulose and amylose continue to be

the most popular. Chiral Technologies

(West Chester, Pennsylvania) reports

that over 85% of the enantiomeric sepa-

rations in the literature are achieved

on one of six such CSPs developed by

them for both HPLC and SFC. In the

standard 250 mm × 4.6 mm format,

they offer the six most popular CSPs on

5-µm particles, plus a 2.1-mm internal

diameter and a 150-mm length. Chiral

Technologies developed 100-mm-long

columns, with 5-μm packings, specifi-

cally for rapid screening by SFC. They

have also introduced two Lindner

phases on 5-μm silica. Finally, they

have also introduced three bonded

(immobilized) phases

ChiralPak IA, IB, and IC, with the

same selectors as AD, OD, and a unique

phase. They are now selling prepacked

columns with internal diameters as large

as 5 cm.

With the expiration of several key

patents, several companies have intro-

duced the equivalent of OD and AD,

in a few new formats. Phenomenex sells

just those two chiral phases, in 3, 5, and

10 µm, and specifically recommends

them for SFC. Regis Technologies

(Morton Grove, Illinois) offers similar

columns, and supports SFC. Of course

Regis also continues to sell many other

stationary phases, including both

enantiomers of Pirkle 1-J, Whelk-O1,

Whelk-O2, Burke2, beta-GEM1, and

others. Akzo-Nobel offers their same

DBM and TBB phases plus an OD and

AD equivalent in 3–25 μm particles.

Astec (now part of Supelco/Sigma

Aldrich) still offers phases based upon

macrocyclic glycoproteins, beta and

gamma bonded cyclodextrins, and a

polymerized cyclic diamine, which have

all been used in the past for SFC. Astec

only mentions “normal phase.”

Conclusions

The turmoil of the past appears to be

over. The path forward seems clear. SFC

is finally stepping out of the shadow of

HPLC and seems destined to experi-

ence robust growth in the near future.

Chiral separations still dominate, but

SFC is not just for chiral anymore. The

inherent speed and resolution of SFC is

being recognized by a much wider base

of chromatographers. There is finally an

active effort on the part of several col-

umn companies to create better columns

with enhanced selectivities, specifically

designed for SFC. The strong trend in

achiral column development is fueled

by an increasing awareness that the high

speed and efficiency, the orthogonal

selectivity, the low-pressure drops, low

operating cost, and the low environ-

mental impact, are general phenomena,

inherent to SFC. SFC appears poised to

enter the area of validated methods (QA,

QC, PV, other trace analysis) in a big

way. The involvement of the two largest

HPLC hardware manufacturers can only

help increase the awareness and

acceptance of the technique.

OPHE

PFP

CN

NH2

EP

SiDIOL

C4

C8

C18

v

E

S

ab

MIX

Figure 3: A five-dimensional representation of column selectivity according to a solvation parameter model. e is excess molar refraction representing polarizability contributions from n and π electrons, v represents the McGowan characteristic volume, s represents diopolarity/polarizability, a and b represent hydrogen bond acidity and basicity. MIX is C18-phenyl Nucleodur SphinzRP, Macherey-Nagel: OPHE is phenyl-propyl, SynergiPolar RP Phenomenex; EP is 2-ethylpyridine, Princeton; C4 is C4 Uptisphere 4, Interchim; PFP is pentafluorophenyl-propyl Discovery HS FS, Supelco. (Adapted from ref. 49).


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www.chromatographyonline.com/majors

Terry Berger and Blair Berger are with Aurora SFC Systems, Inc., Sunnyvale California. Terry Berger has been active in SFC since the early 1980s, first at Hewlett Packard, then Berger Instruments, and is now active in Aurora SFC Systems, Inc. Terry was awarded the Martin Gold Metal in 2004, by the Chromatographic

Ronald E. Majors“Column Watch” Editor Ronald E. Majors is Senior Scientist, Columns and Supplies Divi-sion, Agilent Tech-nologies, and is a member of LCGC’s editorial advisory board.

Society for his contributions to chromatography. Blair Berger graduated from University of Tampa in 2007 with a B.S. in Marine Science, a BS in Biology and a minor in chemistry. Blair has intermittently run SFC instrumentation since 2001, and has been involved with Aurora SFC Systems since its beginnings and has been working as a research assistant for Aurora SFC for six months. Direct correspondence to: [email protected].


LC TROUBLESHOOTING

Look at the big picture. It

may not be appropriate to

obsess on the details.

Too Much Scrutiny

As I write this column, I have

just returned from the Pitts-

burgh Conference in Orlando,

Florida. One of the things that I enjoy

about Pittcon is doing booth duty, when

I get to meet some of you loyal readers

of “LC Troubleshooting.” Sometimes

the conversations turn to specific prob-

lems that you are having with your

liquid chromatography (LC) system

or separation. Often these can be a

mind-stretching conversation with give-

and-take that is not as convenient in

an e-mail exchange. However, some of

these conversations make me realize that

sometimes we all get too focused on the

details of the method without backing

up and determining how they fit into

the big picture. In this month’s column,

let’s look at a couple of examples of this.

Fronting Peaks

In theory, at least, a chromatographic

peak should be Gaussian in shape, with

no fronting or tailing. Nearly every

method, however, has peaks that exhibit

some degree of peak tailing, where the

back edge of the peak does not reach the

baseline as quickly as the front edge rises

from it. We measure peak tailing as either

the asymmetry factor As or the tailing

factor, TF. These are calculated as indi-

cated below with reference to Figure 1:

As = B/A

TF = (A+B)/2A

where A and B are the peak half-

widths, measured at 10% of the peak

height for the asymmetry factor and 5%

of the peak height for the tailing factor.

In past years, methods were plagued

with tailing peaks, especially when basic

compounds were analyzed on the older,

low-purity, type-A silica columns. These

columns had a high population of acidic

silanol groups responsible for tailing.

Today’s newer, high-purity, type-B silica

columns are much less prone to tailing.

In fact, sometimes tailing is so small

that we begin to notice peak fronting.

John W. Dolan

LC Troubleshooting

10% height 5% height

A B

Time

Figure 1: Measurement of peak tailing; see text for details.


One conversation related to peak

fronting of 0.8, as measured with the

asymmetry factor. The person was

very concerned about the source of

the fronting and how to correct it. It

is easy to get off on a conversation

about the sources of fronting peaks,

which, in general, are rare today with

reversed-phase methods. Peak front-

ing is most commonly attributed to

a gross column failure that we some-

times refer to as bed collapse. Some

deterioration of the packing material

takes place and the particles inside

the column shift, creating a void in

the column. This will cause all the

peaks in the chromatogram to front,

and will not be corrected by column

reversal or f lushing. The lady had

replaced the column with a new col-

umn twice and the fronting persisted,

so it is unlikely that column collapse

was the problem. Another possible

problem source is insufficient buffer

in the mobile phase. Also, in the past

I have seen references to peak fronting

in ion-pairing separations being cor-

rected with a change in temperature,

but these methods used type-A col-

umns; I have not seen this on type-B

columns, so a temperature change may

no longer be effective.

As the conversation became more

involved, one of my colleagues, who

was listening, waved the yellow cau-

tion f lag. “Wait a minute,” he said.

“How much fronting are you seeing?”

Well, a little simple math says that an

asymmetry factor of 0.8 is equivalent

to the same peak distortion as a peak

tail of 1.25. The release specifications

that many column manufacturers

use in their quality testing process

indicate that a column with 0.9 < As

< 1.2 is acceptable. In other words,

a brand new column might exhibit a

little fronting or tailing. If the method

we were discussing had an asymmetry

factor of 1.25, we wouldn’t be having

this conversation, would we? As my

daughter used to say, “Don’t sweat

the petty stuff ( . . . and don’t pet the

sweaty stuff ).” This is not a problem

that is worth investigating.

Excessive Recovery

Another Pittcon attendee dropped by to

discuss a problem he was having with

a method for the analysis of a drug in

serum. When he calculated recovery of

the drug from spiked samples, he found

102% recovery. Having low recovery, for

example, 98%, is easy to explain, but he

was concerned about having too much

recovery — how is it possible to recover

more drug than you put in? We must

remember that errors in most laboratory

processes, including sample preparation

and chromatography, are distributed

evenly about the mean. For example, it

is just as likely that a pipette will deliver

0.5% more than the nominal value as

it is to make the same error on the low

side. As a result, the overall error of the

method should be distributed about the

mean value. However, with most sample

preparation processes, we lose sample

along the way, so the average recovery

is <100%. For example, if the average

recovery were 96 ±2%, we would never

see >100% recovery, so when we do

see a method with >100% recovery, we

might be surprised. But there is noth-

ing abnormal about such values.

As the conversation went along,

questions centered on the source of

the error. It turns out that the method

recovery was measured by comparing

extracted serum samples with an aque-

ous reference standard. While this is a

reasonable technique to make a gross

check of overall extraction efficiency,

it is not appropriate for method cali-

bration. With bioanalytical methods

(drugs in biological matrices), the

regulatory guidelines call for a matrix-

based standard curve. This means that

the current method should use blank

serum as the matrix and spike it at the

appropriate concentrations to generate

the calibration curve. This provides

some internal correction for some of

the variables that might be beyond the

control of the user. For example, ion

enhancement or ion suppression with

mass spectrometric (MS) detectors can

be a problem with serum- or plasma-

based methods. By using a matrix-

based standard curve, in which the

calibrators are treated the same as the

samples, it is much like solving simul-

taneous equations in algebra — the

constant factors drop out.


But up comes the yellow flag again!

Why are we having this conversation?

The regulatory guidelines for methods

like this allow for precision and accu-

racy of ±15% at all concentrations

above the lower limit of quantification

(LLOQ) and ±20% at the LLOQ. A

2% error, as in the present case, is insig-

nificant relative to the allowable vari-

ability. There are other fish to fry.

The Lake Wobegon Effect

I am reminded of a story told to me

by a colleague in a laboratory I used to

manage. He had worked for a major

pharmaceutical company that, like most

pharma companies, was very interested

in improving their processes. As part

of the data-gathering process, when

each new LC method was completed,

the time taken to develop the method

was added to a database. After a suf-

ficient amount of data was gathered,

it was possible to calculate the average

method development time for an LC

method. All was well and good until the

next method was developed and it took

longer than the average to complete.

The staff was chastised for poor perfor-

mance because the laboratory manager

expected all methods to be developed in

less than the average time. This reminds

me of Garrison Keillor’s mythical town

of Lake Wobegon that he describes on

his National Public Radio broadcasts.

The tag line at the end of his Lake

Wobegon news always ends with “. . .

and all of the children are above aver-

age.” If the laboratory had sufficient

data to determine a statistically signifi-

cant average, it is unreasonable to expect

all methods to be developed in less

than the average time — duh! Now if

the average represented all LC methods

developed in the pharmaceutical indus-

try, one company’s goal of developing

methods in less than the average time

might be reasonable. Or in a continu-

ous-improvement environment, it might

be reasonable to expect a target develop-

ment time to be less than one standard

deviation above the mean. But all meth-

ods less than the average time? What are

they smoking?

Count the Cost

Another place where we can get dis-

tracted from the big picture is related

to trying to reduce analysis costs. My

guess is that I get this question in at

least half of the LC classes that I teach:

“How can I extend the life of my col-

umn?” Whenever we are looking at

trying to improve a method, we need

to consider the cost. How much does

the current status cost? How much can

I save with the desired change? How

much will it cost me to get there?

Unfortunately, many laboratories

consider the purchase of an LC column

to be a capital expenditure. Yes, it is

expensive, but in terms of the overall

cost of analysis, it should be considered

a consumable item. Do a few calcula-

tions and you’ll convince yourself (and

hopefully your boss). When I was

managing a contract analytical labora-

tory, we often were asked for a quote

for budget purposes. For a typical LC

method with ultraviolet (UV) detec-

tion, we used a number of $50/sample

for this purpose. If I pay $500 for a

column and only get 500 samples

through it before it fails, the cost is

$1/sample for the column. This is

2% of the overall cost of the method

in the present example. A 500-injec-

tion lifetime is pretty short for most

methods, so you might be prompted

to spend some time trying to increase

the column lifetime. Let’s say that you

do some experimentation and find

that by instigating a special clean-

ing procedure, you can extend the

column lifetime to 1000 injections.

Well, you’ve just cut your column

costs in half. This sounds pretty good

until you consider the overall savings.

You’ve reduced the column burden

on the method from 2% to 1%. Is it

worth the trouble? Instead, it might

have been more appropriate to focus

on a more expensive part of the pro-

cess — maybe it is report generation

or sample tracking. There are enough

things to take up our time in the labo-

ratory without creating new ways to

spend time that have little return on

the overall value of the process.

The Big Picture

So, what’s the common thread with

these stories? It is very easy to get


focused on one specific aspect of an

LC method and get distracted from the

overall goal of the method.

In the first case, why is peak asym-

metry of 0.8 a concern? If it is because

we’re not used to seeing fronting

peaks in most LC methods, we might

be worrying about nothing. If it is

because we’re concerned about losing

resolution between that peak and a

small peak that is eluted just in front

of it, then the concern might be more

valid. Should we focus on peak front-

ing or on adjusting the relative peak

positions?

In the second example, recovery

of 102% turned out to be unimport-

ant in the context of a bioanalytical

method with allowable precision and

accuracy of ±15–20%. But if the

method were a pharmaceutical content

uniformity assay, in which ±2% is the

allowable variation, 102% recovery is

a real concern.

Continuous improvement, includ-

ing the reduction of method develop-

ment time, is an admirable goal. But

is it reasonable to instantly expect all

methods to be better than average?

Setting more achievable intermediate

goals for method improvement would

be more reasonable, more likely to

succeed, and certainly better accepted

by the method development staff.

These examples bring to mind

one of my favorite authors when I

was managing a laboratory: Eliyahu

Goldratt (The Goal; It’s Not Luck).

In what some people refer to as a

BFO (blinding f lash of the obvious),

Goldratt introduced me to the concept

of the bottleneck. You can spend all

the time you want trying to improve

a process, but if it does not affect the

rate-limiting step, your efforts will

be of little help. Instead, if you can

improve just this one step, the whole

process will be improved. This prin-

ciple applies very easily to the LC lab-

oratory. Don’t spend too much time

investigating insignificant aspects of

a method — focus on what will really

make a difference.

For more information on this topic,

please visit

www.chromatographyonline.com/dolan


John W. Dolan

“LC Troubleshooting” Editor John W. Dolan is Vice-President of LC Resources, Walnut Creek, California; and a member of LCGC’s edito-rial advisory board. Direct correspondence about this column to “LC Troubleshooting,” LCGC, Wood-bridge Corporate Plaza, 485 Route 1 South, Building F, First Floor, Iselin, NJ 08830, e-mail [email protected]. For an ongoing discussion of LC troubleshooting with John Dolan and other chromatographers, visit the Chromatography Forum discussion group at http://www.chromforum.org.


GC CONNECTIONS

In this month’s “GC

Connections,” John

Hinshaw presents new gas

chromatography products

from the 2010 Pittsburgh

Conference.

John V. Hinshaw

GC Connections Editor

New Gas Chromatography Products at Pittcon 2010

The 61st annual gathering of

the Pittsburgh Conference

on Analytical Chemistry and

Applied Spectroscopy migrated south

to Orlando, Florida, and met Febru-

ary 28–March 5, 2010. On Wednesday

night, Universal Studios’ rides and

attractions were opened to busloads

of conferees who, myself included,

enjoyed rides and attractions that had

not changed much at all since I last

visited with family more than 10 years

ago, save for some updated themes and

new paint. Reminiscences aside, there

was more than a casual similarity to

the Pittsburgh Conference itself, about

which similar statements could be

made. Despite a slightly reduced exhibit

area and an 11% decrease in total atten-

dance, I found this year’s conference

operated at a high level of quality and

efficiency. Nearly all the companies

and key players I needed to meet with

were there, and it was easier to find

them. The technical program was very

well organized, with more than 2348

presentations, seminars, short courses,

and workshops, a slight increase over

the 2009 program in Chicago. Even

as the exhibitor portion of the confer-

ence has shrunk in each of the past few

years, with 46 fewer companies in 2010,

the technical program has remained at

approximately the same size, and in my

opinion, the quality of the presenta-

tions has improved steadily. On March

13–18, 2011, the Pittsburgh Conference

will return to the Georgia World Con-

gress Center in Atlanta, Georgia, for the

first time since 1997.

Since last year’s Pittsburgh Confer-

ence, a number of major industry

announcements have occurred. First

was Agilent’s (Santa Clara, California)

announcement of the intent to acquire

the businesses and products of

Varian, Inc. (Palo Alto, California) As

was made clear at the time and over the

past year, a number of Varian products

Companies Listed in This Column

Agilent

Aurora SFC Systems, Inc. and

Agilent Technologies

Airgas, Inc.

AlphaMOS

Baseline-MOCON, Inc.

Concoa

Entech

Gerstel

Markes International

ModularSFC

NLISIS

Parker Hannifin

PID Analyzers

SGD

SGE, Inc.

Shimadzu Scientific Instru-

ments

Teledyne Tekmar

Thermo Fisher Scientific

Torion

VICI

Wasson-ECE

Zoex

Continued on p. 370


Table I: New instrument systems

Product Name Vendor

GHG Greenhouse gas analyzers Agilent Technologies, Inc.

GC-2010 Plus capillary gas chromatograph Shimadzu

Agilent 1200 Series Analytical SFC system Aurora SFC Systems, Inc. and Agilent

5975T LTM GC/MSD GC–MS system Agilent

Series 9000 H heated hydrocarbon analyzer Baseline- MOCON, Inc.

TSQ Quantum XLS GC-MS/MS Thermo Fisher Scientifi c, Inc.

ISQ single-quadrupole GC–MS system Thermo Fisher Scientifi c

EPC for GUARDION portable GC–MS system Torion


Description

Agilent’s two new greenhouse gases (GHG) analyzers for simultaneous analysis of methane (CH4), carbon dioxide (CO2), and nitrous

oxide (N2O) in air samples also can be used for soil gas analysis or plant breathing studies, where the samples contain CH4, N2O, and

CO2, and both analyzers can be expanded to determine sulfur hexafl uoride (SF6). The GHG analyzers are confi gured on Agilent’s 7890A gas chromatograph with a multivalve micro-ECD methanizer–FID combination that achieves simultaneous analysis of green-house gases in a single injection. A union based on the company’s Capillary Flow Technology connects the valves and the micro-ECD. The analyzers are confi gured and pre-tested in the factory, and they include the method of analysis and complete documentation.

The GC-2010 Plus is a capillary GC with the company’s Advanced Flow Technology (AFT), a redesigned suite of detectors, and fast column fast heating and cooling. AFT consists of digital pressure controllers, additional hardware, and new control software plus room temperature compensation technology that can improve the long-term stability of peak retention times. Two new AFT pack-ages are available: a backfl ush kit and a detector splitting system. The backfl ush system discharges nontarget high-boiling-point components through the injection port split vent to reduce analysis time and control column deterioration and detector contamina-tion. The detector splitting system splits compounds as they are eluted from an analytical column to multiple detectors to obtain multiple chromatograms. The GC-2010 Plus incorporates a new detector series with available fl ame ionization, fl ame photometric, electron capture, fl ame thermionic, and thermal conductivity detectors. The small-sized fl ame photometric detector has improved fl ame stability and double focusing optics to achieve high sensitivities for analysis of phosphorus and sulfur compounds. The fl ame ionization detector utilizes clean detector gas fl ows and the noise reduction technology to ensure high sensitivity with a minimum detected quantity of 1.5 pg C/s. The GC system incorporates a redesigned oven that enables rapid heating and cooling. A double-jet cooling system employs air fl ow channels that yield a cooling time from 450 °C to 50 °C of 3.4 min.

Aurora SFC Systems, Inc. and Agilent Technologies have signed an OEM agreement under which Agilent will sell and support a com-bined system: the Agilent 1200 Series Analytical SFC system. This system combines the Agilent’s 1200 Series Rapid Resolution Liquid Chromatography system with the Aurora SFC Fusion A5. According to the company, the new SFC system delivers a 10-fold increase in sensitivity compared to existing SFC solutions. This increase is achieved by applying carbon dioxide fl ow delivery with the same pulse-less precision as is achieved for water and organic solvents. The system has a dynamic range greater than 20,000:1. Operating costs can run from one-tenth to one-fi fteenth of existing SFC systems to operate because the new system uses standard-grade carbon dioxide instead of highly expensive SFC-grade liquid carbon dioxide. Installation of the Aurora SFC Fusion A5 with the Agilent 1200 RRLC System is reversible so the Agilent instrument can still be used in RRLC confi guration.

The 5975T Low Thermal Mass (LTM) GC/MSD from Agilent is a transportable GC–MS system that delivers laboratory-quality analysis in the fi eld, according to the company. The system is smaller and consumes less power than in-lab GC–MS instruments. By wrapping the GC column with a heating element and temperature sensor, the LTM component achieves rapid heating and cooling of the column for higher sample throughput. The transportable system reduces power consumption by 46%, shrinks the footprint by 38%, and reduces weight by 35% compared to the company’s conventional laboratory gas chromatographs. The LTM column module can be exchanged in the fi eld. The 1.8–1050 u mass range electron impact (EI) inert ion source and quadrupole mass analyzer produces NIST-searchable spectra. The 5975T LTM GC/MSD is said to be well-suited for chemical warfare analysis, fi rst responders, and military and homeland security offi cials. Additional applications include food safety testing and environmental monitoring. An optional liquid autoinjector is available.

Baseline-MOCON, Inc. introduced its new heated hydrocarbon analyzer for applications that require the sample to stay heated above its dew point. The Series 9000 H heated hydrocarbon analyzer is confi gured for single point analysis with an active detection range from less than 30 ppb hydrocarbons expressed as methane in the high sensitivity version, and up to 50% hydrocarbons as methane in the percent level version. Standard outputs include alarm and fault relays, 0–20 mA/4–20 mA analog, RS-232 or Ethernet. Applica-tions for the Series 9000 H include continuous emission monitoring (CEM), scrubber and oxidizer effi ciency, carbon bed breakthrough detection, lower explosive limit (LEL) monitoring, vehicle emissions, chemical process blending, and compliance monitoring for EPA Methods 25A & 503. The 9000 H has a large graphical display and includes on-board diagnostics, factory and local contact informa-tion, help menu, and a service reminder for preventative maintenance. The included Series 9000 Keeper software provides total control of the instrument method, alarms, relays, calibration, and confi guration, plus data export and real-time viewing.

Thermo Fisher Scientifi c Inc. introduced the TSQ Quantum XLS triple-quadrupole GC–MS system that features the company’s DuraBrite IRIS high sensitivity ion source. Equipped with optional column backfl ush capability, the TSQ Quantum XLS enables high-throughput laboratories to run increased QuEChERS extract samples for 24/7 routine operation. Exchangeable inert ion volumes are replaceable without venting the vacuum system. The high sensitivity ion source, hyperbolic quadrupole rod analyzer, and 90° zero cross-talk collision cell deliver low femtogram detection limits. Up to 3000 selected reaction monitoring (SRM) scans can be time programmed in one chromatogram. Multiple reaction monitoring (MRM) combined with quantitation-enhanced data-dependent MS-MS (QED-MS-MS) provide simultaneous quantitation and structural confi rmation. A pesticide analyzer confi guration is accompa-nied by the Pesticides Method Reference manual, with more than 600 pesticide compounds. The TSQ Quantum XLS can be changed from EI mode to chemical-ionization (CI) mode without venting the system. It also can be converted between GC and LC modes.

Thermo Fisher Scientifi c showed the ISQ single-quadrupole GC–MS system with nonventing full-source removal capability. The ISQ system features the company’s ExtractaBrite removable ion source, a mass range from 1.2 to 1100 u, and sequential full scan–selected ion monitoring (SIM) capability. The ISQ acquires and writes data to disk at rates of up to 60 u/s across 125 u. It is offered with either the Thermo Scientifi c FOCUS GC system for routine GC–MS or with the TRACE GC Ultra for additional fl exibility and performance. The system comes standard with the latest version of the Thermo Scientifi c QuanLab Forms GC–MS acquisition, analysis and reporting software package. Available options include chemical ionization, with positive chemical ionization (PCI) for molecular weight con-fi rmation, negative chemical ionization (NCI) for enhanced selectivity and sensitivity, and pulsed positive ion–negative ion chemical ionization (PPINICI) standard for alternating PCI and NCI scans in a single injection. DEP/DIP direct sample probes are available as well.

Torion Technologies Inc. announced the availability of electronic pressure control (EPC) for its GUARDION-7 GC-TMS system. The EPC system uses voltage-sensitive orifi ce valves to control and program carrier gas for the GC. The GC–MS system can program its column at greater than 2 °C/s, has a mass range of 50 to 500 Da, and is hand-portable with a built-in helium supply cartridge. The company also introduced a new, PC-based software application, CHROMION-1, for the GUARDION-7. The software manages the instrument’s system functions using an Ethernet connection with a portable laptop computer and features method, calibration, and library func-tions for quick method editing, instrument calibration, and target compound library development.


Table II: New instrument accessories

Product Name Vendor

Meltfi t column guide NLISIS Chromatography

Remote gas monitoring Airgas, Inc.

AroChemBase library AlphaMOS

Zero air generator Parker Domnick Hunter

AutoLogic-II 918 Series automatic changeover manifold SGD, Inc.

CFC-3 centrifugal fraction collector Modular SFC

Advanced Cooling System for GC Wasson-ECE

Fast GC single-column heating unit VICI


Description

NLISIS Chromatography announced its semiautomatic Meltfi t column guide that allows analysts to plug GC columns into the injector and detector. The Meltfi t is a universal docking system that enables plug-and-play installation and removal for all regular GC systems and columns. The docking system is fi xed permanently into the GC oven to guide column ends into the injector and detector interfaces. The column is installed into a Meltfi t Column Holder, an open cassette structure, that can be prepared outside the GC system. The ends of the column are fi tted out with a Meltfi t tube and a special bullet shaped connector. The cassette is positioned on a support in the Meltfi t column guide. and the column “bullets” are inserted into the injector and detector by gently moving a lever and a clamp. The structure prevents leakage or cold spots. The system provides a uniform mechanism and procedure for column installation and removal without requiring an assortment of different column ferrules and nuts for each GC system type.

Airgas, Inc. showed a new line of remote gas monitoring systems for laboratory gases, including a low-cost wired system and two wireless systems to monitor gas pressure or liquid levels in cylinders. The systems also monitor temperatures and contact opening and closing. The basic remote monitoring system uses a wired connection and monitors gas pressure from up to 16 sources. It has indicating pressure switches and can send e-mail alerts when pressures and gas cylinder volumes reach preset levels. Systems can be added to standard alarm panels that are rated NEMA 4, Class I, Division II, Group B, and are suitable for all inert and fl ammable gases, with the exception of acetylene. The wireless module can monitor data from any device with a gauge face or that produces a 4– 20 mA or a 0–5 V dc signal. The system transmits the information to either a computer network or cellular telephone hub, which in turn calls or sends a text message alert. Airgas’ Smart Logic Manifolds, a line of fully automatic programmable logic controller (PLC)–based change-over manifolds, are connected to a laboratory computer network. The system can be confi gured for high-pres-sure cylinders, liquid cylinders, or a combination of the two. The system monitors a variety of data and can provide alerts to notify staff when a cylinder change out has occurred, or that an empty cylinder needs to be replaced. It can also alert staff when detecting unusually high volumes of gas usage, which could indicate a leak. An option for the gas manifold systems monitors the frequency of changeover from the active gas supply to the reserve gas supply and alerts the user that they could be overdrawing liquid cylinders.

Alpha MOS introduced a new database for aroma and chemical characterization by GC analysis. The AroChemBase library uses the Kovats Index as a reference method. It includes 2900 compounds of which 1400 have sensory attributes, with chemical information including name, formula, CAS number, molecular weight, and retention index. It is available for several columns: methylpolysiloxane, methyl 5% phenyl polysiloxane, cyanopropylphenyl 14% dimethyl polysiloxane, and polyethylene glycol. Used with a two-column GC-based electronic nose or GC system, it yields dual column identifi cation and ranking. The library proposes a list of possible compounds for a selected peak in a chromatogram. Compounds are sorted by a unique recognition accuracy index. This index is based on the comparison of measured parameters of retention time plus peak area on one or two columns along with theoretical parameters. The higher the index, the higher the probability of correspondence. The database can be enhanced by including user data and it is also possible to extract tailored sublibraries.

Parker introduced a new zero air generator range that utilizes core platinum catalyst technology to produce clean dry hydrocarbon-free air. An external supply of compressed air is prefi ltered and passed through a heated platinum catalyst module where the air stream is oxidized to remove organic impurities. The resulting hydrocarbon-free air stream can give increased detector signal-to-noise ratios. The zero air generators has a residual methane content of less than 0.1 ppm when supplied from an existing compressed air supply. Models are available with fl ow rates ranging from 1.0– 30.0 L/min. An interchangeable top panel allows for direct mounting of a Parker Domnick Hunter UHP hydrogen generator to provide an integrated fl ame gas solution for GC–fl ame ionization, fl ame photometric, and nitrogen–phosphorus detector applications. The generators can also be used to supply zero air to nebulizer and exhaust gas for LC–MS applications, zero gas and combustion gas for total hydrocarbon analyzers and calibration–dilution gas for gas sensing equipment.

The 918 Series AUTO-LOGIC II changeover manifold from SGD is constructed with brass or stainless steel high purity gas components. It has digital pressure readouts for inlet pressures and outlet delivery pressure, built-in alarms, and dry contacts to operate external equipment, such as remote alarms or an auto-dialer. The system is housed in a NEMA 4X enclosure. The system features a color touch screen that shows constant digital and graphic gas supplies on both sides. A delivery pressure monitor displays any unusual variances, and there are high and low adjustable delivery pressure alarm settings. A leak-check monitoring function alerts the user to low reserve side pressure of either high pressure or cryogenic containers while in standby, via audible and visual alarms. There are built-in audio and visual alarms and external dry contacts that can activate optional equipment or remote alarms. The system is available in either brass or stainless steel construction. It has a maximum inlet pressure of 3000 psig (20 mPa).

Modular SFC’s CFC- 3 centrifugal fraction collector collects up to 24 SFC fractions from commercial SFC systems at atmospheric pres-sure into standard glass collection tubes, bottles, or scintillation vials. The device dries the fractions while collecting with recoveries greater than 95%. The system’s Centrifan recirculating evaporation blows rotor chamber gas into the collection tubes. Centrifugal force generated by the rotor captures nonvolatile sample from the eluant fl ow stream. The centrifugal force also maintains frac-tion integrity as the Centrifan delivers more than 160 cfm of airfl ow or inert gas to the fraction solutions. The rotor chamber is at atmospheric pressure during the collect–dry operation so no vacuum pump is required. The fraction collector fi ts in a fume hood or on a lab bench. Vapors are directed through an exhaust hose that can be connected to the laboratory vent system. The system is controlled via the company’s CFC-PC software, which allows collection by slope, threshold, and time. A graphical interface provides fraction identifi cation.

Wasson-ECE displayed its Advanced Cooling System (ACS) cryogen-free column cooler. The external unit houses a single column at temperatures from ambient down to 0 °C that operates in tandem with the primary GC oven at a higher temperature. The system is

designed for low-temperature separations such as Ar and O2, SO2, and OCS, and N2 and O2 without the need for a liquid nitrogen or

CO2 cyrogen supply.

VICI showed the Fast GC single-column heating unit for nickel-wire and nickel-clad resistively heated capillary GC columns. The GC column assembly mounts inside a conventional GC column oven and includes an auxiliary cooling fan. The controller has 8 program-mable temperature states and can ramp temperatures at up to 800 °C/min with an isothermal accuracy of 0.1 °C and a programmed accuracy of < 0.5 °C. A Windows-based control program communicates with the controller by USB or I2C bus.


will not be acquired by Agilent, notably

the gas chromatography (GC) division

at Varian-Chrompack (Middleburg, The

Netherlands) and the mass spectrometry

(MS) business in Walnut Creek, Cali-

fornia. Shortly after this year’s Pittcon,

Bruker (Billerica, Massachusetts)

announced its intention to acquire these

product segments. At the time of this

publication both transactions have yet

to complete. In addition to this, C2V

(Enschede, The Netherlands), a manu-

facturer of micro gas chromatographs,

was acquired by Thermo Fisher Scien-

tific (Waltham, Massachusetts). These

transactions are another sign of industry

consolidation in the current economic

climate. Yet, the GC instrument busi-

ness appears to be going strong, with no

fewer than eight new instrument prod-

uct announcements at Pittcon 2010.

This annual “GC Connections”

installment reviews GC instrumenta-

tion and accessories shown at this

year’s Pittcon or introduced during

the previous year at conferences such

as ASMS or Analytica. For a review

of new chromatography columns and

accessories, please see Ron Majors’

“Column Watch” column in the March

and April 2010 issues of LCGC (1,2).

The information presented here is

based upon manufacturers’ replies to

questionnaires, as well as on additional

information from manufacturers’

press releases, websites and product

literature, and not upon actual use or

experience of the author. During the

conference, I took time to walk around

the convention aisles and see some of

the new products firsthand as well as

discover a number of items that weren’t

covered by the questionnaires. Every

effort has been made to collect accurate

information, but due to the prelimi-

nary nature of some of the material,

LCGC cannot be responsible for errors

or omissions. This article cannot be

considered to be a complete record of

all new GC products shown at this

year’s Pittcon because not all manufac-

turers chose to respond to the

Table III: New sampling accessories

Product Name Vendor

Selectable 1D/2D GC–MS system Gerstel

7150 headspace preconcentrator Entech

eVol dispensing syringe system SGE Analytical Science

Microchamber thermal extractor Markes International

TD-100 thermal desorption system Markes International

AQUATek 100 waters-only autosampler Teledyne Tekmar

Continued from p. 364


questionnaire, nor is all of the submit-

ted information included here due to

the limited available space and the edi-

tors’ judgment as to its suitability.

New Instruments

The number of new GC instruments

increased this year in comparison to

2009, with multiple introductions from

both Agilent and Thermo Fisher Scien-

tific, plus a new instrument from Shi-

madzu (Columbia, Maryland) as well as

some other interesting offerings. In par-

ticular, the Agilent GHG Greenhouse

Gas analyzers represent a continuing

interest in “green” analytical chemistry

such as PerkinElmer’s (Waltham, Mas-

sachusetts) EcoAnalytix platforms. In

addition, Agilent showed the 5975T

transportable Low Thermal Mass

(LTM) capillary column GC–MS sys-

tem that is aimed at chemical warfare

analysis, first responders, and military

and homeland security officials as well

as food safety testing and environmen-

tal monitoring. The Agilent 1200 Series

Analytical supercritical f luid chroma-

tography (SFC) system also is included

in this year’s listing. Although not a gas

chromatograph, the system’s supercriti-

cal f luid mobile phase is gas-like in its

physical characteristics, and arguably, it

is equally at home in either GC or liq-

uid chromatography (LC) circles.

Thermo Fisher Scientific also

brought two new GC systems to the

conference. The TSQ Quantum XLS

GC–MS-MS system is a high-perfor-

mance triple-quadrupole system with

a number of unique new features that

make it stand out. The ISQ single-

quadrupole GC–MS system lies on the

other end of the GC–MS spectrum as a

routine workhorse instrument with an

excellent pedigree.

From Shimadzu, the GC-2010

Plus capillary gas chromatograph is

a completely updated version of the

company’s 2010 series that includes

new detectors, Advanced Flow Tech-

nology, backf lushing and detector split

options, and rapid oven cooling. In

addition, Baseline-MOCON (Lyons,

Colorado) brought in its new Series

Description

Gerstel introduced the Selectable 1D/2D GC–MS system that performs routine single-dimensional GC–MS analysis and can be switched on demand to perform two-dimensional separation for more complex matrices. Interesting sections of the chromatogram can be collected and concentrated from multiple runs and then transferred to a second GC column with different polarity to isolate trace compounds The system is based on a single standard GC–MS instrument. Both columns are installed in the same GC system and are heated independently using Low Thermal Mass (LTM) technology. The system supports heart-cutting with cryofocusing from multiple repeat injections on a Gerstel Cryo Trap System (CTS). The complete system is controlled from the Gerstel MAESTRO software, fully integrated with the GC–MS software. One method and one sequence table controls the complete system.

The Entech 7150 headspace preconcentrator can recover C2 to C25 compounds from parts-per-million to sub-parts-per-billion levels, including thermally labile compounds. Three stages perform headspace preconcentration, with a fi rst stage that implements what

the company calls “Active SPME” to allow compounds from C12 to C25 to be trapped and recovered quantitatively. Moisture and lighter volatile compounds not retained in the fi rst stage pass through a cold trap where water is removed by a direct vapor/solid

transition. The C2–C10 fraction is collected onto a liquid CO2–cooled Tenax trap at -40 °C. After water is removed using a short

bakeout, the Tenax trap is back desorbed and refocused onto the fi rst stage SPME trap at -60 °C. The C2–C25 fraction is transferred simultaneously to the GC column.

The eVol dispensing syringe system from SGE couples a digitally controlled electronic drive and one of the company’s interchange-able XCHANGE enabled analytical syringes to produce a digitally controlled positive displacement dispensing system that can be programmed to reproducibly and accurately perform a wide variety of liquid handling procedures. Dispensed volumes are user independent. The device features a familiar touch wheel user interface and a full-color screen. The eVol can be calibrated with a gravimetric calibration procedure and the calibration factors can be stored and loaded for up to 10 syringes. Only three XCHANGE syringes are required to dispense liquid volumes covering the range from 200 nL to 500 μL. A full range of needles and replacement parts is available from the company.

Markes International Ltd. launched of a new version of its Micro-Chamber/Thermal Extractor (μ-CTE) for the measurement of (S)VOC (volatile and semivolatile organic compounds) such as formaldehyde. The new extractor assists compliance with new legislation such as REACH (Registration, Evaluation and Authorisation of Chemicals), CARB (California Air Resources Board), and EC (European Com-mission) Construction Products Directive/Regulations that require products and materials to be sent to independent test laboratories for certifi cation of chemical release and additional quality control of chemical emissions. The new instrument allows four samples (each up to 114 mL volume) to be evaluated simultaneously at temperatures up to 250 °C. Bulk or surface-only emissions of (S)VOC, including key phthalate plasticizers, can be sampled from a wide variety of materials including construction products, semiconduc-tor/PC components, car trim, carpets, paints, textiles, and children’s toys. The μ-CTE is usually used in combination with sorbent tubes and offl ine thermal desorption (TD) GC–MS. Additionally, the company’s μ-CTE units are compatible with DNPH (2,4-dinitrophenylhydrazine) cartridges for formaldehyde emissions screening by HPLC.

The TD-100 thermal desorption system from Markes International incorporates electrical cooling and sample re-collection for repeat analysis, and couples to any make of GC or GC–MS system. It is capable of the sequential analysis of up to 100 sorbent tubes and includes RFID sample sorbent tube tracking technology (TubeTAG) as standard. The TD-100 is designed for the sampling and analysis of trace toxic and odorous chemicals (VOC and SVOC) in air/gas and materials. Relevant application areas include materials emissions testing for compliance with construction products regulations or REACH (Registration, Evaluation and Authorisation of Chemicals), environmental–indoor air monitoring, workplace air monitoring, food, fl avor and fragrance profi ling, civil defense, and forensics.

Teledyne Tekmar introduced the AQUATek 100 waters-only autosampler. The AQUATek 100 is a purge and trap autosampler that automates sample preparation steps for the analysis of liquid samples. It utilizes a fi xed volume sample loop that is fi lled using a pressurization gas. Two independent volume programmable internal standards are added to the sample and the entire aliquot is transferred to the purge-and-trap sampler for compound concentration and subsequent separation and detection using a GC or GC–MS system. This instrument replaces the company’s AQUATek 70 autosampler. The AQUATek 100 offers 30% more sample capac-ity than the previous model. Autoblanking allows more vial positions to be used for samples rather than required quality control blanks by generating blanks from the built in water reservoir. The standard vial cooling system allows samples to be chilled to 10 °C before analysis.


9000 H heated hydrocarbon analyzer

for applications that require samples

to stay heated above its dew point, and

Torion (American Fork, Utah) updated

its GUARDION-7 GC-TMS portable

GC–MS system with electronic pres-

sure control (EPC) pneumatics and

new external PC control software.

General Accessories

A number of useful and unique GC and

SFC accessories appeared at Pittcon 2010.

NLISIS Chromatography (Veldhoven,

The Netherlands) enhanced its Meltfit

tube sealing system with a column guide

system that facilitates the installation

and removal of columns from a GC oven

with plug and play capability. AirGas

(Radnor, Pennsylvania) introduced a

series of remote gas monitors that track

and alert on low gas supply pressures and

levels, and SGD (Emerson, New Jersey)

showed the new AutoLogic-II 918 Series

changeover manifold that works with

both cryogenic liquid and high-pressure

gas cylinders. Alpha MOS (Hanover,

Maryland) introduced the AroChemBase

library database for aroma and chemical

characterization\ by GC analysis; the soft-

ware uses the Kovats Index as a reference

method. Parker Domnick Hunter (Char-

lotte, North Carolina) displayed a new

zero air generator range that utilizes core

platinum catalyst technology to produce

clean dry hydrocarbon-free air and can be

stacked with the company’s other labora-

tory gas generators.

From Modular SFC (Franklin, Mas-

sachusetts), the CFC-3 Centrifugal

Fraction Collector is an enhanced ver-

sion of the company’s fraction collectors

for SFC. The Fast GC Single Column

Heating Unit from VICI (Houston,

Texas) mounts a nickel-clad capillary

GC column in the main GC oven and

controls the temperature and high-speed

ramps. Also in the column temperature

control category, the Advanced Cooling

System (ACS) column cooler from Was-

son-ECE (Fort Collins, Colorado) takes

the opposite approach of cooling the

column as required, but without

needing cryogenic coolant.

GC Detectors

The detector category came up a little

short with only two entries, but both

represent significant advances in their

respective technologies. The FasTOF

high-resolution time-of-flight mass

spectrometer from Zoex (Houston,

Texas) has very high performance

specifications, with resolution greater

than 5000 at the midpoint of its mass

range and a maximum 500-Hz spec-

tral acquisition rate that makes it well

suited to the demands of comprehensive

GC×GC. From PID Analyzers (Pem-

broke, Massachusetts), the model PI-51

photoionization detector can be added

to any conventional GC system and

features improved detection limits and

dynamic range compared to previous

detectors from the company.

GC Sampling and Accessories

Quite a few companies introduced

sampling accessories this year. Gerstel

(Linthicum, Maryland) featured a

unique Selectable 1D/2D GC–MS sys-

tem that controls whether a sample is

subject to a single or dual dimensional

separation on a standard GC–MS

instrument equipped with the acces-

sory. The model 7150 headspace pre-

concentrator from Entech (Simi Valley,

California) is capable of recovering

volatiles and semivolatiles up to C25

at sub-parts-per-billion levels before

GC analysis. From Teledyne Tekmar

(Mason, Ohio), the AQUATek 100

Waters-only Autosampler is a purge-

and-trap autosampler that automati-

cally generates sample blanks from a

built in water reservoir. Markes Inter-

national, Ltd. (New Haven, Connecti-

cut) launched of a new version of its

Micro-Chamber/Thermal Extractor (µ-

CTE) for the measurement of (S)VOC

(volatile and semivolatile organic

I look forward

to finding more

unique new

GC and related

products that

demonstrate its

ongoing viability

and sustained

innovative growth

at Pittcon 2011.

GE

TT

Y I

MA

GE

S


Table IV: New GC detectors

Product Name Vendor Description

Model PI-51 PID photoionization detector

PID Analyzers The PID Analyzers model PI-51 photoionization detector consists of a photoionization detector and a constant current power supply that powers the lamp and supplies the accelerat-ing voltage. It also comes with an adapter for various GCs. An existing fl ame ionization detector amplifi er is used for the pho-toionization signal. The PI-51 is 200 times more sensitive than a fl ame ionization detector for aromatics, 80 times more sensitive

for olefi ns, and 30 times more sensitive for alkanes above C6. Compared to the company’s other photoionization detectors, the model PI-51 has improved detection limits for aromatic compounds, from 2 ppb down to 0.5 ppb, and an increased dy-

namic range, from 1 x 107 up to 5 x 107. The detector measure 2.5 in. x 5.5 in. and the electronics enclosure weighs 4.5 lb.

FasTOF high-resolution time-of-fl ight mass spectrometer for GCxGC

Zoex Zoex Corporation introduced the FasTOF, a high resolution time-of-fl ight mass spectrometer detector for GCXGC. The system provides mass resolution of 4000–7000 (tunable) at 281 Th, full range mass spectra at up to 500 Hz (100 Hz typical), mass measurement accuracy of +/- 0.002 Th across the PFK mass range, and sensitivity of 100:1 S/N for 1.0 pg OFN on-column. A pulsed mass calibration system compensates for temporal drift in mass calibration parameters. GC Image software fully supports high resolution mass spectrometric analyses, including exact mass measurements and elemental composition determi-nations.


compounds) such as formaldehyde, as

well as the TD-100 thermal desorption

system, which incorporates electrical

cooling and sample recollection for

repeat analysis, and couples to any

make of GC or GC–MS system.

SGE Analytical Science (Austin,

Texas) showed its eVol dispensing

syringe system, a combination of one

of the company’s interchangeable

XCHANGE enabled analytical syringes

with a handheld programmable elec-

tronic dispenser for highly repeatable

dosing of liquid volumes covering the

range from 200 nL to 500 µL.

Conclusion

While Pittcon 2010 was the smallest

Pittsburgh Conference in quite a few

years, I will risk predicting that next

year’s conference in Atlanta will see a

significant increase in attendance and

exhibitor booths. I won’t imply that

moving up to Atlanta qualifies as a

move to the “North” as I certainly

don’t want to insult any Peachtree

aficionados, but it is true that previ-

ous conferences’ relative attendance

levels generally correlate with the

number of degrees of north latitude. I

look forward to finding more unique

new GC and related products that

demonstrate its ongoing viability

and sustained innovative growth at

Pittcon 2011.

Acknowledgment

I would like to thank the manufac-

turers and distributors who kindly

furnished the requested information

before, during, and after Pittcon

2010, allowing a timely report on

new product introductions. For those

manufacturers who did not receive a

preconference questionnaire this year

and would like to receive one and be

considered for early inclusion into

Pittcon 2011 coverage, please send the

name of the primary company contact,

the mailing address, fax number, and

e-mail address to David Walsh, Edi-

tor-in-Chief, LCGC North America, c/o

Advanstar Communications, 485 Rte.

1 South, Bldg. F, Iselin, New Jersey

08830, Attn.: Pittcon 2011 New GC

Products, or e-mail to:

[email protected].

References

(1) R. Majors, LCGC 28(3), 192 (2010).

(2) R. Majors, LCGC 28(4), 274 (2010).

(3) F.J. Schenck and J.E. Hobbs, Bull. Environ.

Contam. Toxicol. 73(1), 24–30 (2004).

John V. Hinshaw

“GC Connections”

editor John V. Hinshaw

is senior Research

Scientist at Serve-

ron Corp., Hillsboro,

Oregon, and a member

of LCGC’s editorial advi-

sory board. Direct correspondence about

this column to LCGC, Advanstar Communi-

cations, 485 Rt. 1 S, Bldg F, 1st Floor, Iselin,

NJ 08830, or contact the author via e-mail:

[email protected].


please visit

www.chromatographyonline.com/hinshaw



Pittcon is one of

the world’s premier

conferences and

expositions on laboratory

science. It is a showcase

for the latest advances in

laboratory instrumentation

and technology, attracting

more than 1,000 exhibiting

companies from around

the world, including of

course, all of the major

HPLC vendors. This one-

stop-shopping Mecca

makes it a great place

for vendors to introduce

(and for scientists to see,

touch, evaluate, compare,

and hear) all about the

latest in HPLC technology.

This installment of

“Innovations in HPLC”

will highlight some of the

new HPLC and related

technology introduced

at the conference.

Michael Swartz

Innovations in HPLC Editor

INNOVATIONS IN HPLC

Many high performance liquid

chromatography (HPLC)

vendors have for years coor-

dinated their new product development

cycle around the Pittcon schedule,

planning to introduce new technol-

ogy at the conference for the first time.

Although the proliferation of additional,

specialized conferences has altered this

approach somewhat in recent years (for

example, many new mass spectrometry

[MS] new product introductions are now

made at ASMS), Pittcon still remains a

real must-go-to meeting to see the lat-

est and greatest in HPLC and related

technology. Because Pittcon attracts

nearly 20,000 attendees from industry,

academia, and government from over

90 countries worldwide, the conference

provides a great opportunity for ven-

dors to expose new HPLC products to

both new and existing customers. For

the attendees, the conference provides a

venue to evaluate the latest instrumenta-

tion, compare vendors, participate in

product demonstrations, and to speak

with technical staff to resolve problems

or investigate potential applications.

At this year’s Pittcon, held Febru-

ary 28–March 5 in Orlando, Florida,

several vendors introduced new systems

and components, as well as product line

extensions. In this installment of “Inno-

vations in HPLC,” I’ll review some of

the new HPLC instrument technology

shown at the conference; new column

and sample preparation technology will

be reviewed by Ron Majors in his “Col-

umn Watch” column. The information

in this review is partially based upon

manufacturers’ responses to a preconfer-

ence questionnaire mailed in late 2009.

I have used the information received in

the questionnaires that were returned,

as well as information from personal

visits to as many vendors as I could dur-

ing the conference to try to make this

review as comprehensive as possible. But

keep in mind that due to the fact that

some manufacturers did not respond to

the questionnaire, or do not release pre-

show information — and because of the

the sheer size of the conference — this

report cannot be considered an exhaus-

tive listing of all new products that were

introduced in Orlando. I’m bound to

have missed a few items or details, so I’ll

apologize in advance for any omissions.

Table I lists the product introductions

reviewed in this column.

UHPLC Systems

HPLC is a proven technique that has

been used in laboratories worldwide

over the past 30-plus years. One of

the primary drivers for the growth of

this technique has been the evolution

of packing materials used to effect the

separation. As the column particle size

decreases to less than 2.5 µm, not only

is there a significant gain in efficiency,

but the efficiency does not diminish at

increased flow rates or linear velocities.

By using smaller particles, speed and

peak capacity (number of peaks resolved

per unit time) can be extended to new

limits. This technique is referred to as

ultrahigh-pressure liquid chromatogra-

phy (UHPLC) (1,2). UHPLC takes full

advantage of chromatographic principles

HPLC Systems and Components Introduced at Pittcon 2010: A Brief Review


to run separations using higher flow

rates and columns packed with smaller

particles for increased speed and supe-

rior resolution and sensitivity. UHPLC

was first introduced at Pittcon 2004 in

Chicago, with the introduction of the

Waters Acquity UPLC system (Waters

Corp., Milford, Massachusetts) and

reports claim that UHPLC systems will

exceed 50% of the market by the year

2013. Several manufacturers have intro-

duced UHPLC systems of their own

in the years since 2004. This year in

Orlando was no exception, where new

systems, system variations, and compo-

nents were introduced.

Building upon the success of the

Prominence LC-20A Series, Shimadzu

Scientific Instruments (Columbia,

Maryland) introduced the Nexera

UHPLC system, billed as an all-around

HPLC system that enables various

types of analysis including conventional

HPLC, ultrafast LC, and UHPLC at

pressures up to 19,000 psi, at flow rates

ranging from 100 nL/min to 5 mL/min.

The binary pump uses microsapphire

plunger-driven pistons (10-µL pump

head volume) in a parallel design, with

mixing accomplished in an innova-

tive low delay volume, ultrahigh-speed

microreactor design, called the MiRC,

as shown in the schematic in Figure

1. The XYZ-style injector features a

through needle design with a fixed-loop

option for fast analyses, with an injec-

tion cycle as short as 10 s, and injection

volumes of 0.1–50 µL. To reduce the

delay volume in the injector, an omega-

shaped rotor design is used that reduces

tubing lengths and the number of con-

nections required. Up to three rinse

liquids can be programmed to rinse the

inside and the outside of the needle, as

well as the injection port to minimize

carryover. In pretreatment mode, the

autosampler is also capable of perform-

ing precolumn derivatizations, additions

of internal standards, and dilutions. The

Nexera Rack Changer has temperature

control (4–40 °C) and a capacity of up

to 12 sample plates for a total of up to

4608 samples. The column oven can

go up to 150 °C (nice for “green” 100%

water mobile phase use), and has a two-

column capacity. It incorporates a sol-

vent preheater (referred to as the Intel-

ligent Heat Balancer-IHB) that adjusts

and balances the mobile phase tempera-

ture according to the flow rate and the

column set temperature to minimize the

affect of frictional heating at the head of

the column. The total system delay vol-

ume is less than 42 µL with the ultra-

low volume (20 µL) mixer, optional

loop injection kit with 5-µL loop and

microvolume preheater. Absorbance,

fluorescence, and MS detector applica-

tions were shown.

Following in the footsteps of the

innovative Acquity UPLC System,

Waters (Milford, Massachusetts)

Figure 1: Schematic of the Shimadzu MiRC micro reactor–mixer. The MiRC uses a unique channel structure on a microchip that allows mobile phase components to be stacked on top of each other to form a multi thin layer in the microchannel. The reactor design, originally used in organic synthesis, shortens the diffusion time in the micro channel, providing effective mixture of solvents.

Table I: Summary of systems and components reviewed in this column

VendorBrief New Technology Description

Web Site

Agilent Technologies

1290 Infinity Multi-method system6100B SQ MS Detector

www.agilent.com/chem

CVC Micro TechKing Kong Nano-, Micro- XPLC, and Analytical-HPLC

www.cvcmicrotech.com

Dionex CorporationUltiMate 3000 RSLC NanoICS-5000 Reagent-Free Capillary IC

www.dionex.com

Eksigent Technologies

ExpressHT-UltraExpressLC-Ultra

www.eksigent.com

Hitachi High Technologies America

LaChromUltra amino acid analysis UHPLC system

www.hitachi-hta.com

Leap Technologies CTC PAL autosampler www.leaptech.com

Quant Technologies, LLC

NQAD QT-700 detectorwww.quanttechnolo-gies.com

Shimadzu Scientific Instruments, Inc.

Nexera UHPLCRF-20A and RF-20Axs FL detectorsLC-20AP preparative LC pump

www.shimadzu.com

Thermo Scientific Accela 1250 pump www.thermo.com

Unimicro Technologies Inc.

TriSep-2100 pCECwww.unimicrotech.com

Waters CorporationAcquity UPLC H-Class systemAcquity UPLC system for glycan characterization and SEC analysis

www.waters.com


introduced its next generation UHPLC

instrument called the ACQUITY

UPLC H-Class system. The H-Class

system combines the flexibility of

quaternary solvent blending and a

flow-through-needle injector to bring

the features of the original UPLC

instrument to a wider HPLC audi-

ence. The ACQUITY UPLC H-Class

was designed to allow organizations to

standardize their approach to LC with

a common technology platform that

makes the future transition from HPLC

to UPLC sub-2-µm technology-based

methods straightforward and practical.

The H-Class quaternary low-pressure

mixing system uses a separate gradient

proportioning valve for each solvent

and a five-chamber integrated vacuum

degassing system — four for the solvent

lines, one dedicated to the injector nee-

dle wash for added precision. Flow can

be programmed from 0.010 to 2.000

mL/min, in 0.001-mL/min increments,

with a maximum operating pressure of

15,000 psi up to 1 mL/min, or 9000

psi up to 2 mL/min, with a total system

volume of under 400 µL. For method

development, the H-Class Quaternary

Solvent Manager (QSM) can be used

to prepare mobile phases on the fly, or

“Autoblend,” a technique that has been

used in HPLC for many years. Premix-

ing solvents during method develop-

ment can be wasteful, as mobile phase

combinations are tried that ultimately

might not be used in the final method.

Autoblend avoids having to discard

unused mobile phase as individual neat

solvents are used, making it easier to

maintain pH and ionic strength and

resulting in more robust methods. In

addition, optional, integrated software-

controlled solvent select valves increases

to nine the number of solvents that can

be evaluated during method develop-

ment, and with the addition of column

switching valves, the number of discreet

methods that can be run on one system.

In the original ACQUITY UPLC

System, the sample manager uses a loop

injector, and a choice between different

injection procedures (full loop, partial

loop, with and without overfill) can be

made with the method objectives (accu-

racy, precision) in mind. The more tra-

ditional HPLC autosampler-type flow-

through needle design in the H-Class

sample manager can be used in both

the HPLC and UHPLC mode, which

makes the transition between tech-

niques much simpler. Because the entire

needle is flushed with mobile phase

from the method, a complete, quantita-

tive transfer of the sample is accom-

plished, which results in better accuracy

and precision and decreased carryover.

In addition, the way the flow path is

managed keeps the sample in the tip of

the needle. When the flow is reversed to

the column during the actual injection,

dispersion that can lead to decreased

resolution is minimized. The design

also minimizes dispersion when an

extension tube is added when perform-

ing larger volume injections. H-Class’s

patent-pending SmartStart Technology

automatically manages gradient start

time and preinjection steps in parallel to

reduce inject-to-inject cycle times to less

than 30 s. The H-Class uses what the

company calls Quantum Synchroniza-

tion to synchronize the injection with

the pump stroke to improve precision

(retention time reproducibility). Injec-

tion volumes of 0.1–10.0 µL are stan-

dard, and an optional extension loop

can extend the volume to 250.0 µL.

Samples can be maintained in a temper-

ature-controlled environment at 4–40

°C. An active integrated programmable

needle wash is used, and the sample

manager can perform autodilution and

sample transfer routines.

Several new column oven options

complete the H-Class system package.

The standard CH-A column heater

can accommodate a single column (up

to 150 mm × 4.6 mm) at 20–90 °C

(dependent upon ambient temperature,

requiring a setting 5 °C above ambient

for control). A second option is a CM-

A column manager that includes two

selection valves, one inlet, and one out-

let. The CM-A can accommodate two

columns (up to 150 mm × 4.6 mm) at

4–90 °C, and it has both heating and

cooling capabilities to operate below

ambient room temperature. Column

capacity can be increased by adding up

to two additional CHC-A modules, for

a total of six columns with automatic

random access switching, individual

temperature control (each column can

be at a different temperature), and waste

and bypass positions for rapid solvent

changeovers in method development or

multimethod use. All three of the col-

umn devices (CH-A, CM-A, and CHC-

A) include an active preheater (APH)

cartridge (one independently controlled

cartridge for each column position) that

can be turned on or off — the latter in

case you need to run a legacy passive

heating method — and eCord column

information management that tracks

and archives column usage history. A

final option called the CH30-A accom-

modates two columns as large as 300

mm × 4.6 mm at 20–90 °C (dependent

upon ambient temperature) and includes

the inlet and outlet selection valves. It is

intended that any combination of these

column devices can work together in a

single system. The H-class can be used

with the existing line of photodiode-

array (PDA), tunable UV, evaporative

light scattering, fluorescence, single

and tandem quadrupole MS detectors,

as well as the sample organizer that

depending upon the type of plates used,

can extend the sample capacity from

768 (standard) to over 8000.

Thermo Fisher Scientific (Waltham,

Massachusetts) introduced the model

1250, a new pump version to enhance

its Accela system, extending the pressure

range and adding additional capabilities.

The Accela 1250 pump is a quaternary

pump that uses Thermo’s Force Feed-

back Control (FFC) technology that

continually autocalibrates valve timing

and pumping efficiency based upon the

actual measured compressibility of sol-

vents. The result is extremely low pulsa-

tion (lower than 0.5 bar amp.) without

the need of a pulse dampener. FFC tech-

nology is also utilized in the Thermo

600 series pumps (8700 psi). The model

1250 extends the operating pressure of

the Accela system to over 18,000 psi, at

flow rates of 1–2000 µL/min with a low

pressure mixing system delay volume

under 70 µL. The 1250 is incorporated

into the Accela system first introduced

in 2005 and uses the existing Accela

autosampler and PDA detector.

Eksigent (Dublin, California) came

out with the ExpressHT-Ultra and

ExpressLC-Ultra systems designed

for micro- and high-throughput opera-

tion (respectively) at up to 10,000

psi to take advantage of sub-2-µm

column technology. Using a binary


pneumatically driven pump the number

of moving parts is significantly reduced,

and with Microfluidic Flow Control

(MFC) technology, the flow rate is

continuously monitored and a feedback

loop makes fast, real-time adjustments

to maintain flow and gradient repro-

ducibility. Both systems include an

industry-standard CTC autosampler

(Leap Technologies, Carrboro, North

Carolina) capable of injection volumes

as low as 50 nL. As configured with

the CTC autosampler, the Eksigent

systems have one of the smallest foot-

prints of any systems on the market.

The ExpressHT-Ultra is designed for

1-mm i.d. HPLC column operation and

bioanalytical applications with inject-to-

inject cycle times as low as 60 s. Flow

rates of 50–200 µL/min are standard,

with a gradient delay volume of less

than 10 µL. The ExpressLC-Ultra is

designed for 0.5-mm i.d. HPLC column

operation for improving sensitivity. The

system uses a CCD-based UV detec-

tor with a microfabricated fiber-optic

flow cell with either 5- or 10-mm opti-

cal pathlengths or volumes as small as

90 nL. Flow rates of 1–50 µL/min are

standard, with a gradient delay volume

of 1.2 µL.

The Shimadzu Nexera, Waters

ACQUITY H-Class, the Thermo Accela

1250, and the Eksigent ExpressHT-

Ultra and ExpressLC-Ultra systems join

the Waters ACQUITY UPLC, Agilent

1290 Infinity (Santa Clara, California),

Dionex Ultimate 3000 (Sunnyvale, Cali-

fornia), PerkinElmer Flexar (Waltham,

Massachusetts), Hitachi LaChromUltra

U-HPLC (Pleasanton, California), and

the Jasco X-LC (Easton, Maryland) in

sub-2-µm column capability, proof that

UHPLC is here to stay.

Specialty HPLC–UHPLC Systems

For the purposes of this review, I’ll

define specialty systems as systems con-

figured for a particular test, application,

or use. For Pittcon 2010, Agilent intro-

duced the 1290 Infinity Multi-method

System, a multicolumn and multi-

solvent selection system. In the UHPLC

version of the Agilent Multi-method

and Method Development Solution,

pressures up to 16,800 psi at 2 mL/min

and 11,200 psi at 5 mL/min in binary

operation, or 5600 psi at 5 mL/min and

2800 psi at 10 mL/min in quaternary

operation can be used. The system is

based upon a 1290 Infinity System

(Pittcon 2009 introduction) using a

cluster of up to three thermostatted

column compartments with integrated

eight-column ultrahigh-pressure selec-

tion valves mounted on a slide-out rail

for easy installation and maintenance.

The system also can accommodate up to

two 12-position solvent-selection valves,

and both the column and solvent-selec-

tion valves can be chosen through

software radio buttons showing the

column’s name or by a dropdown menu

showing the solvent names. The quick-

change valves have radio-frequency

identification (RFID) tags on the valve

heads providing documentation of the

valve type, serial number, number of

switches, and the pressure setting.

The design facilitates open access,

software-selectable unattended and


automated use of multiple separation

conditions; at capacity, the combina-

tion of eight columns (if a waste or

bypass is used the number of columns

is reduced) and 26 solvents results in

over 1000 unique separation conditions

for binary separations. Column dimen-

sions up to 300 mm × 4.6 mm can be

accommodated, with six separate heat-

ing zones (up to 100 °C). The system

can be run in conjunction with method

development software packages such as

ChromSword (Iris Technologies, Olath,

Kansas) automated method optimiza-

tion software, the Agilent ChemStation

Method Scouting Wizard software,

and Advanced Chemistry Development

(ACD/Labs, Toronto, Ontario, Canada)

ChromGenius software. Existing model

1290 Infinity autosamplers can be used,

or a new high-throughput injector. A

range of detectors is also available that

includes multiple, variable, and diode-

array UV, fluorescence, refractive index,

evaporative light scattering, and the new

6100 Series Quadrupole MS system.

When the model “T” first came out,

Henry Ford used to say: “You can have

any color you want-as long as it’s black.”

Similarly, in 2004, when UHPLC

was first introduced, you could have

any column you wanted, as long as it

was C18. These days, there are many

more column flavors available, many of

which are scalable between HPLC and

UHPLC particle sizes. Many vendors

now have columns available over a wide

variety of chemistries and particle sizes,

and have configured method develop-

ment, validation, and transfer kits that

contain an assortment of columns, chem-

istries, and column–method calculators

all designed to take the guess work out of

method development, method migration

(HPLC to UHPLC), and method trans-

fer. Capitalizing on its column chemistry,

Waters introduced three application-spe-

cific systems based upon the ACQUITY

line. For the characterization of 2-

AB–labeled glycans from glycoproteins,

Waters has combined its UHPLC glycan

columns with the ACQUITY system

equipped with fluorescence detection. An

example separation using this system is

shown in Figure 2. Current FDA regula-

tions recommend that firms developing

and manufacturing therapeutic proteins

are able to accurately characterize the

glycans attached to those proteins to

ensure the efficacy and safety of a bio-

pharmaceutical product. In 35 min or

less, the system can profile an array of

oligosaccharides including high man-

nose and complex, hybrid, and sialylated

glycans. For separating and quantifying

monoclonal antibodies (mAb) and their

aggregates in less than 4 min, Waters

has combined its BEH200 1.7-µm size-

exclusion chromatography columns with

the ACQUITY system, making it faster

and easier for manufacturers to achieve

high-quality data that meets FDA rec-

ommendations for quantifying protein

aggregates suspected of being capable

of producing an immunogenic response

in some patients. A complementary line

of high-resolution ion-exchange col-

umns also were introduced for protein

separations. Waters also introduced an

alternative to off-line solid-phase extrac-

tion (SPE) by combining the ACQUITY

system with on-line, automated SPE,

providing analyte extraction, concentra-

tion, separation, and detection in one

automated solution.

Another application-specific system

was introduced by Hitachi: the LaChro-

mUltra Amino Acid Analysis UHPLC

system. The system is based upon

Hitachi’s UHPLC system, and is for the

1

4

5

6

7

8

9

10

11

2

3

12

13

Time (min)

EU

25000.000

20000.000

15000.000

10000.000

5000.000

0.000

10.00 15.00 20.00 25.00 30.00 35.00

Figure 2: Example glycan analysis using UHPLC. Sample: 2AB-labeled human-IgG N-glycans (Prozyme, San Leandro, California) at 10 pmol/µL. Column: 150 mm X 2.1 mm Acquity UPLC BEH Amide; mobile phase: gradient of 100 mM ammonium formate (pH 4.5)–acetonitrile over 50 min; temperature: 60 °C; flow rate: 0.5 mL/min; detection: fluorescence (λex = 330 nm, λem = 420 nm); injection volume: 1.5 µL (partial loop). Peaks: 1 = G0, 2 = G0F, 3 = Man5, 4 = G0FGN, 5 = G1, 6 = G1Fa, 7 = G1Fb, 8 = G1FGN, 9 = Man6, 10 = G2, 11 = G2F, 12 = G1F+SA, 13 = G2F+SA.


rapid high-resolution analysis of amino

acids via precolumn derivatization. It is

capable of analyzing amino acids in a

broad range of sample types including

protein hydrolysates, foodstuffs, and cell

culture media.

Shimadzu Scientific Instruments was

also showing their new, next-generation

LC-20AP Preparative LC pump, which

can be used for analytical, semiprepara-

tive, and preparative LC applications

(without changing pump heads) at flow

rates of 0.01–150 mL/min at high pres-

sure (6000 psi up to 100 mL/min and

4350 psi up to 150 mL/min). These

flow rates and pressures make it possible

to use 250 mm × 50 mm, 5-µm par-

ticle size columns to achieve high-reso-

lution and high-efficiency purifications

and improve productivity. Using higher

resolution microstepping motor control,

the pump can be used at analytical

flows (for example, 1 mL/min), so that a

user can develop a method at analytical

scale and then immediately convert it

for preparative scale on the same system,

improving productivity.

Capillary–Nano HPLC Systems

Several new nano systems and a capil-

lary system were introduced in Orlando.

Dionex introduced the ICS-5000

Reagent-Free IC (RFIC) system, a capil-

lary ion chromatography (IC) system

with the ability to analyze samples at

capillary, microbore, or standard ana-

lytical flow rates (or any combination

of two in a dual system, termed 2D

IC). In capillary mode, the ICS-5000

system reduces eluent consumption over

100-fold compared to standard analyti-

cal scale operation, which translates to

only about 2 L of solvent consumption

over several months. Another benefit

of capillary IC is that parts-per-trillion

level sensitivity can be obtained, again

100-fold better than standard analytical

scale detection limits. The heart of the

system is the IC Cube, which accom-

modates cartridge-based consumables

like columns and suppressors that can

be added or changed easily. The system

can be configured with two IC Cubes

to facilitate running two applications at

the same time in 2D-IC mode. The 2D

IC mode allows an analyst to perform

both anion and cation analysis with one

injection, perform two different anion

applications, or eliminate dilutions from

unknown samples by running the same

application with large loop–small loop

injections. Using the capillary mode,

analysis times are reduced to less than

5 min for the analysis of seven anions

or five cations. as illustrated in Figure

3. The ICS-5000 single pump option

can be configured with either capillary

or analytical pump heads to support

capillary, microbore, standard bore, or

semipreparative applications. The pump

is upgradeable from a single to a dual

pump yielding either a dual capillary,

dual analytical, or hybrid (capillary and

analytical) pump, which also supports

the option of gradient (proportioning

valve) operation. In capillary mode, the

ICS 5000 has a 6000-psi maximum

operating pressure and is capable of

flows up to 3 mL/min in 0.0001-mL/

min increments. In analytical mode,

it has a 5000-psi maximum operating

pressure and is capable of producing


a 10.000-mL/min flow, adjustable in

0.001-mL/min increments. The pump

heads, mixing chamber, and flow path

are all composed of inert PEEK mate-

rial, and the system has an integrated

piston seal wash and built-in vacuum

degasser. Dual-zone thermal control

(10–70 °C for the detectors, depending

upon the compartment, and 5–85 °C

for the column) provides two indepen-

dent temperatures for both the column

and the detectors; a thermostatted

autorange conductivity detector and

an electrochemical detector provide

increased flexibility and utility.

Nano HPLC is a technique that

generally involves the application of

columns with an internal diameter of 75

µm and flow rates of approximately 300

nL/min. They are ideal for sample-

limited applications requiring high sen-

sitivity, such as in proteomics. Dionex

also unveiled a system offering in the

nano category, called the UltiMate

3000 RSLC Nano system. The RSLC

Nano system is available in dual config-

urations that facilitate preconcentration

and sample clean-up steps, and make

multidimensional and parallel separa-

tions possible. Continuous direct mobile

phase flow (no splitting) is delivered by

four pistons (two per solvent channel)

so that unlike a syringe-driven pump,

a refill cycle is not required — during

flow delivery of one piston, the other

is refilled, and after the refill cycle,

the refilled piston is pressurized and

takes over the flow delivery. Flow rates

ranging from 20 nL/min to 50 µL/min

are possible at a maximum pressure of

11,200 psi. All critical flow paths are

maintained under temperature control,

and injections down to 20 nL are pos-

sible. The RSLC Nano system also is

capable of automated off-line 2D-LC

using combined autosampling and

microfraction collection.

CVC Microtech (Fontana, California)

also premiered a new system, called the

Nano-XPLC system. The Nano-XPLC

system is configurable in many different

ways; single, dual, ternary or quater-

nary pumping, and in what the com-

pany refers to as “Dual Core” binary

mode. In dual core binary mode, one

pump is performing a separation, while

the second is equilibrated, increasing

throughput. The Nano-XPLC can also

be configured as a micro or analytical

HPLC. Flows and pressures range from

10 nL/min to 20 µL/min at 20,000 psi

on the Nano-XPLC, 0.1 µL/min to 2.2

mL/min at 20,000 psi on the Micro-

HPLC, and 1 µL/min to 10 mL/min at

6000 psi on the Analytical HPLC. All

systems are capable of being configured

as single up to quaternary pumps or the

2-D dual-core mode. Systems include

a variable-wavelength UV detector,

a temperature-controlled (4–40 °C)

autosampler accommodating up to five

microtiter plates, and an option that

includes a combination autosampler–

fraction collector that can also function

as a matrix-assisted laser desorption ion-

ization (MALDI) spotter. A wide range

of column chemistries and applications

was shown.

New HPLC Detectors

Detectors for condensation nucleation

light scattering detection (CNLSD)

are a form of light scattering aerosol

detectors that are used in the same type

of applications suited for evaporative

light scattering detection (ELSD) (3).

In CNLSD, following evaporation of

the mobile phase, a saturated stream of

solvent is added to the particles in the

carrier gas. The particles form conden-

sation nuclei and the solvent condenses

onto the particles, increasing their size

to the point where they are detected

more easily in the light path. Due to the

increase particle size, CNLSD can be

10–100-fold more sensitive than ELSD,

with a wider linear range. At Pittcon

2010, Quant Technologies (Blaine,

Time (min)

Co

nd

uct

ivit

y (

µS)

9

1

9

10 3 6 9 12

(b)

(a)

12

3 45

6

7

1

2

34

5

6

7

Co

nd

uct

ivit

y (

µS)

Figure 3: Capillary anion separation: (a) 250 mm X 4 mm IonPac AS22, (b) 150 mm X 4 mm IonPac AS22-Fast. Eluent: 4.5 mM sodium carbonate–1.4 mM sodium bicarbonate; flow rate: 1.2 mL/min; temperature: 30 °C; injection volume: 10 µL; detection: capillary suppressed conductivity. The excess resolution of the 250 mm column is marked in green.


Minnesota) introduced the NQAD

QT-700, a third detector in their line of

CNLSD systems for HPLC, UHPLC,

and SFC (Quant Technologies sold

the original two detectors in their line

through Grace, but now sell all detec-

tors in their line direct). Aerosol-based

detectors are very useful for applications

that involve compounds that do not

have a UV chromophore or fluorophore;

however, they are destructive detec-

tors, which makes fraction collections

and solvent recycling cumbersome.

The NQAD QT-700 remedies this by

splitting the flow internally to accom-

modate built in fraction collection and

solvent recycling options. Fraction col-

lection allows the chromatographer to

isolate individual sample components

even if they do not contain a chromo-

phore or fluorophore without cumber-

some derivatization steps. Like the

Quant QT-600, the 700 is also meant

for UHPLC applications; the 500 for

HPLC.

Shimadzu Scientific Instruments

introduced two new fluorescence detec-

tors, the RF-20A and RF-20Axs. Utiliz-

ing a newly designed optical system, and

a xenon lamp with extended lamp life-

times, Shimadzu claims these detectors

have the highest sensitivity levels of any

HPLC fluorescent detector. Response

times as fast as 10 ms allow use in ultra-

fast LC applications without a loss of

separation, and wavelength switching

via a time program allows simultane-

ous testing of multiple components at

optimal wavelengths for highly sensitive

multicomponent analyses. Because fluo-

rescence intensity drops as temperature

increases (a 1 °C change can result in a

5% response difference for some com-

pounds), the RF-20Axs features a tem-

perature-controlled cell with a cooling

function to compensate as the environ-

mental temperature fluctuates, ensuring

reproducibility without decreasing sensi-

tivity. Applications highlighting amino

acid, reducing sugar, and carbamate

pesticide analysis were shown.

Also in the detector category, Agilent

introduced the 6100B Series single-

quadrupole LC–MS system. The B

Series uses Agilent’s Jet Stream Thermal

Gradient Focusing Technology to pro-

vide a wide ionization range and added

sensitivity. The 6100B is optimized for

high-throughput injections and comple-

ments the Agilent 1290 Infinity Multi-

method system, particularly when using

peak tracking software in method devel-

opment mode.

“Light-pipe” or “light-guided” flow

cells have been used for some time, par-

ticularly in the newer UHPLC systems

to minimize dispersion (4). Agilent

introduced new detector cell technol-

ogy for their diode-array detector that,

like light-pipe or light-guided flow cells,

utilizes the principle of total internal

reflectance along a noncoated fused-

silica capillary to increase sensitivity and

minimize dispersion. Called Max-Light

flow cells, two versions are available in

a very convenient “plug and play” car-

tridge format.

Conclusion

I saw a lot of additional noteworthy

items at Pittcon, but time, space, and

the scope of this column really pre-

vent me from covering them all in any

amount of detail. I was particularly

intrigued by the number of major

HPLC vendors (for example, Agilent

and Waters) exhibiting supercritical

fluid technology, which might be a part

of the green chemistry movement in

some respects, although using SFC for

the separation of chiral compounds is

also a great fit. I also spent some time

looking at the Unimicro Technolo-

gies (Pleasanton, California) pressur-

ized electrochromatography system,

the TriSep-2100 pCEC. While I don’t

believe the TriSep pCEC system was

new for this Pittcon, I hadn’t had a

chance to look at it before, and the

combination of small-particle pressure-

driven flow and electrophoresis provides

some rather unique high-efficiency

separations.

A number of vendors (Agilent,

Thermo Fisher Scientific, Waters, and

others) also exhibited systems based

upon the CTC PAL Autosampler. Some

used valves to create customized solu-

tions or spatial arrangements to produce

a small footprint.

Many vendors were also showing che-

mometric HPLC software for applica-

tions such as database tracking of meth-

ods (Dionex), method development and

robustness evaluation according to qual-

ity-by-design (QbD) principles (Waters),

or peak tracking method development

and experimental design (Agilent, ACD/

Labs [Toronto, Canada]).

And finally, while not an instrument

or component, but certainly related,

another notable HPLC introduction

was made in the Wiley (Hoboken, New

Jersey) booth. The third edition of

Introduction to Modern Liquid Chroma-tography is now available, a book that

should be on every chromatographer’s

bookshelf (5).

In 2011, Pittcon will return to Atlanta

March 13–18. Hope to see you there!

References

(1) The Quest for Ultra Performance in Liq-

uid Chromatography — Origins of UPLC

Technology, Waters Corporation. See:

http://www.waters.com/waters/partDetail.

htm?cid=511539&id=38628&ev=10120661

&locale=en_US

(2) Beginners Guide to UPLC — Ultra-Per-

formance Liquid Chromatography. Waters

Corporation. See: http://www.waters.com/

waters/partDetail.htm?cid=511539&id=386

29&ev=10120684&locale=en_US

(3) M. Swartz, J. Liq. Chromatogr., in press, July

2010.

(4) M. Swartz, LCGC 27(12), 1052–1057,

(2009).

(5) L.R. Snyder, J.J. Kirkland, and J. Dolan,

Introduction to Modern Liquid Chromatog-

raphy, 3rd Edition (John Wiley and Sons,

New York, 2009).



please visit


Michael Swartz

“Innovations in

HPLC” Editor

Michael E. Swartz is

Research Director at

Synomics

Pharmaceutical

Services, Wareham,

Massachusetts, and

a member of LCGC’s editorial advisory

board. Direct correspondence about

this column to “Innovations in HPLC,”

at [email protected].


Jessika De Clippeleer,* Filip Van Opstaele,* Joeri Vercammen,† Gregory J. Francis,‡ Luc De Cooman,* and Guido Aerts*

*KaHo St-Lieven, Laboratory of Enzyme, Fermentation, and Brewing, Ghent, Belgium.

†Interscience Expert Center, Louvain-la-Neuve, Belgium.

‡Syft Techologies UK, Warrington, UK.

Direct Correspondence to:[email protected].

Real-Time Profiling of Volatile Malt Aldehydes Using Selected Ion Flow Tube Mass Spectrometry

Malt, the main raw material

for beer production, is made

from selected cereal grain,

usually barley (Hordeum vulgare L.), by

steeping, germination, and drying (kiln-

ing). By varying the processing parame-

ters during germination and drying, vari-

ous types of malt are obtained (1). The

strong influence of malt composition on

final beer quality and beer flavor stabil-

ity is generally acknowledged (2–4). In

particular, flavor stability remains one of

the main quality criteria for beer, and the

urgency to control it is endorsed by the

global beer market and its allied need for

longer storage times for exported beer.

Formation and release of volatile alde-

hydes is recognised as one of the main

causes of beer flavor deterioration upon

storage (5–7). Most of these compounds

pre-exist abundantly in malt, and can

vary significantly between different malt

types. As such, the staling potential of

finished beer is determined largely by the

type of malt used in the brewing process

(8–12). Therefore, each modern brew-

ery that aims at a pleasant and consis-

tent beer flavor has to take appropriate

measures from the onset of the brewing

process by selecting high-quality malt.

Consequently, knowledge of malt alde-

hyde content is indispensable for brewers

in view of quality control, selection of

the appropriate malt variety, and objec-

tive assessment of flavor stability of the

processed beer.

Different procedures have been applied

to isolate carbonyl compounds from malt

(13,14). Their isolation from the complex

malt matrix is far from easy and requires

an appropriate sample preparation proce-

dure. Traditional extraction techniques

such as vacuum distillation or continu-

ous steam distillation–solvent extrac-

tion (that is, Likens–Nickerson extrac-

tion) with subsequent Kuderna–Danish

evaporation before gas chromatography

(GC) analysis, are very cumbersome and

time-consuming (15,16). To increase

throughput and selectivity and maintain

sensitivity, headspace analysis, preferably

in combination with solid-phase micro-

extraction (SPME), is the method of

choice (16). SPME is a well-known sam-

ple preparation technique that is solvent-

free, fast, inexpensive, easily amenable

to GC, and has proven to be extremely

powerful for analyzing volatile as well

as semivolatile compounds at trace and

ultratrace levels (17).

The potential of selected ion flow tube mass spectrometry (SIFT-MS)

to differentiate malted barley cultivars on the basis of their headspace

profiles has been investigated. From a broad range of volatiles, marker

aldehydes were selected because they are associated with malt quality

and beer flavor stability. The authors used dynamic headspace SIFT-MS

to identify the target volatiles in the different malt headspaces. The

technique exhibited an increase in specificity and speed compared with

the headspace solid-phase microextraction (SPME) gas chromatography–

MS method currently used. The unique feature of SIFT-MS to analyze

sample headspaces rapidly and directly without the need for sample

preparation, derivatization, or chromatographic preseparation is

demonstrated.


Unfortunately, headspace SPME

of malt and beer samples suffers from

the interference of other compounds

that are abundant in the matrix. To

eliminate these interferences, SPME

of aldehydes generally is carried out in

combination with a selective extraction,

on-fiber derivatization, for example, with

o-(2,3,4,5,6-pentafluorobenzyl)hydroxy

l-amine (PFBHA) (18–20). Converting

the aldehydes to their pentafluoroben-

zylhydroxylamine derivatives is not only

beneficial with respect to extraction selec-

tivity but also has a positive effect on GC

performance. Additional effects, which

are due predominately to the nature of the

SPME procedure — that is, equilibrium

extraction — and which hamper accurate

quantification, require the use of internal

standards and standard addition, which

complicates the overall procedure even

further. Moreover, milling and exposure

to ambient air during sample preparation

and extraction induces the pro-oxidative

enzyme potential of malt, which leads to

the formation of unwanted artifacts and a

severe risk of biased results.

Selected ion flow tube mass spectrom-

etry (SIFT-MS) is an analytical technique

that is based upon soft chemical ionization

taking place in a flow tube reactor. First

introduced by Smith and Spanel, SIFT-

MS is now an established technique for

volatile organic compound (VOC) analy-

sis that has advantages over many other

analytical approaches (21). SIFT-MS pro-

vides a quantitative measure of analytes in

air mixtures in real time at sensitivities in

the low parts-per-billion (ppb) level, and

more recently, the parts-per-trillion (ppt)

level without the need for external cali-

bration (absolute quantification) (22,23).

These very low quantification limits are

enabled by a thorough understanding of

the chemical kinetics of an analyte with

each of the SIFT-MS reagent ions H3O+,

NO+, and O2+ (21,24).

Initially, the instrumentation used to

exploit the SIFT-MS technique was large

and cumbersome and only able to be oper-

ated by highly skilled laboratory scientists.

Furthermore, early SIFT-MS instruments

had very poor limits of detection due to

low ion currents. New instrumentation

specifically designed for quantitative mea-

surements often will generate total ion sig-

nals greater than 2 × 107 cps, which leads

to routine measurements in the parts-per-

trillion range being possible (23,25,26).

To properly utilize SIFT-MS as an

analytical technique, at a level that will

provide analyte quantification, requires

knowledge of rate coefficients, product

ion channels and their respective branch-

ing ratios, reactions of the water cluster

ions with the analyte, and secondary reac-

tions of major product ions with H2O.

Currently, the database of this knowl-

edge contains over 400 compounds that

can be quantified by SIFT-MS without

Microchamberthermal extractor

Zero airgenerator

Syft

VOICE200

Figure 1: Schematic representation of the analytical set-up for volatile malt composition analysis by dynamic headspace SIFT-MS.

Table I: Overview of SIFT-MS parameters. The branching ratio is the frac-tional probability (represented as a percentage) of a product ion being formed from a single reaction between an ion and an analyte.

Component ReagentBranching ratio (%)

Mass Product

2,3-Butanedione NO+ 65 86 C4H6O2+

Formaldehyde

H3O+ 100 31 CH3O+

O2+ 40 29 HCO+

O2+ 60 30 H2CO+

Acetaldehyde H3O+ 100 45 C2H5O+

Hexanal NO+ 100 99 C6H11O+

trans-2-PentenalNO+ 95 83 C5H7O

+

NO+ 5 114 C5H8O.NO+

trans-2-HexenalNO+ 85 97 C6H9O+

O2+ 30 69 C5H9

+

trans-2-HeptenalNO+ 85 111 C7H11O

+

NO+ 15 142 C7H12O.NO+

trans-2-OctenalNO+ 80 125 C8H13O+

NO+ 20 156 C8H14O.NO+

trans-2-NonenalNO+ 80 139 C9H15O+

NO+ 20 170 C9H16O.NO+

trans,trans-2,4-Decadienal

H3O+ 100 153 C10H17O+

2-Methylpropanal NO+ 100 71 C4H7O+

2-Methylbutanal NO+ 98 85 C5H9O+

3-Methylbutanal NO+ 100 85 C5H9O+

Methional NO+ 95 104 C4H8OS+

Phenylacetaldehyde H3O+ 100 121 C8H8O.H+

Benzaldehyde H3O+ 100 107 C7H7O+

Furfural H3O+ 100 97 C5H5O2+


the need for an external calibrant.

A unique feature of SIFT-MS is its

ability to quickly and directly analyze

the headspace samples mentioned ear-

lier, without requiring specific sample

preparation or derivatization techniques.

Moreover, the use of three reagent ions,

generally, creates sufficient selectivity for

real-time analysis without the need for

(time-consuming) chromatographic sepa-

rations. The SIFT-MS application range is

already very broad and is still broadening

as this article goes to press. Applications

such as breath analysis (21,27), environ-

mental monitoring (28), oil exploration

(29), ambient air monitoring for occu-

pational safety and health (30), and the

detection of chemical warfare agents (26)

and peroxide-based explosives (31) have

been published recently.

In this article, we present our results

on the evaluation of dynamic headspace

SIFT-MS to discern volatile profiles and

composition of various malted barley

cultivars. Prime focus is on the analysis

of aldehydes and particularly as com-

pared to the headspace SPME procedure

currently used.

Experimental

Reagents: All chemicals were purchased

from Sigma-Aldrich (St. Louis, Missouri)

at the highest purity available.

Malt Samples: Five different malt sam-

ples were used during this study. All were

produced from barley on industrial scale,

and referred to as A, B1, B2, B3, and C.

Three different barley cultivars were dis-

tinguished: A, B and C. From the single-

variety industrial malt B, three different

harvest years were studied — B1, B2, and

B3. Samples A, B1, B2, and B3 were sup-

plied by the same malting plant.

Head space SPM E G C – MS

Analysis: Volatile aldehydes in malt were

quantitatively determined according to

Vesely and colleagues (19). Extraction of

marker aldehydes from CO2-milled malt

samples (0.25 g in 10 mL water) was

performed by headspace SPME with on-

fiber PFBHA derivatization using a 65-

μm PDMS-DVB coated fiber (Supelco,

Bellefonte, Pennsylvania). The PFBHA

(1 g/L) was loaded during 10 min at 50

°C, after which extraction and derivati-

sation was carried out for 30 min. The

carbonyl derivatives were analyzed using

a TraceGC/DSQ II GC–MS system

(Thermo Fisher Scientific, Madison, Wis-

consin) purchased at Interscience (Lou-

vain-la-Neuve, Belgium). The system was

equipped with a CTC CombiPAL autos-

ampler, a split–splitless injector with nar-

row-bore glass inlet liner, and an RTX-1

fused-silica capillary column (40 m ×

0.18 mm, 0.2-μm film thickness, Restek).

Helium was used as carrier gas at 0.8 mL/

min. The inlet temperature was set at 250

°C, and injection was carried out in split

mode (split ratio 50:1). The oven tempera-

ture was kept at 50 °C for 2 min, then

raised to 210 °C at 6 °C/min, followed by

an increase to 250 °C at 15 °C/min, and

finally held at 250 °C for 5 min. The MS

transfer line was set at 260 °C. Ionization

of the carbonyl derivatives was obtained

by electron ionization and the main frag-

ment ion (m/z = 181) was detected in the

single ion monitoring scan mode (19).

Data were processed with XCalibur soft-

ware (Thermo Fisher Scientific).

SIFT-MS Analysis: A commercial

SIFT-MS instrument (Voice200, Syft

Technologies, Christchurch, New Zea-

land), was used for this work. The system

was equipped with a direct inlet and a

heated external interface, which provided

Table II: Overview of volatile aldehydes in the headspace of different malts after headspace SPME GC–MS expressed in µg/kg malt. All compounds were PFBHA derivatized and detected by monitoring m/z = 181 in SIM mode.

ComponentMalt sample

A B1 B2 B3 C

Hexanal 173 ± 10 705 ± 37 834 ± 27 1010 ± 41 736 ± 5

trans-2-Nonenal 29 ± 2 41 ± 1 58 ± 2 74 ± 3 66 ± 3

2-Methylpropanal 612 ± 17 1668 ± 41 1885 ± 5 2311 ± 39 1475 ± 99

2-Methylbutanal 467 ± 21 829 ± 19 952 ± 19 1119 ± 111 749 ± 82

3-Methylbutanal 1213±137 3270±308 3674±120 4197±192 4271±341

Methional 281 ± 29 366 ± 11 224 ± 7 377 ± 5 566 ± 5

Phenylacetal-dehyde

400 ± 19 725 ± 46 736 ± 31 853 ± 35 617 ± 70

Benzaldehyde 64 ± 4 81 ± 3 86 ± 23 93 ±10 99 ± 16

Furfural 285 ± 6 291 ± 46 404 ± 63 416 ± 1 412 ± 30

Heated external interface

Siltek treated tube, 1/8 in. o.d.

Restriction, 1/16 in. o.d.

Heated PTFE block

TD tube with frit

Figure 2: Schematic drawing of the SIFT-MS system’s heated external interface with module for direct coupling to a microchamber–thermal extractor.


direct entry to the flow tube. The exter-

nal interface was Siltek treated (Restek) to

minimize activity.

Target compounds were analyzed using

selected ion mode (SIM). Here, abundance

is derived from the measured signal inten-

sity at the specific product ion masses. The

following compounds were targeted: 2,3-

butanedione, formaldehyde, acetaldehyde,

hexanal, trans-2-pentenal, trans-2-hexenal,

trans-2-heptenal, trans-2-octenal, trans-

2-nonenal, trans,trans-2,4-decadienal,

2-methylpropanal, 2-methylbutanal, 3-

methylbutanal, methional, phenylacetal-

dehyde, benzaldehyde, and furfural. All

relevant instrumental settings, target and

product ions, monitored reactions, and

branching ratios are summarized in Table

I. The majority of the data was obtained

from a proprietary compound library data-

base included with the instrument (25).

Care was taken not to induce any conflicts

in selecting target product ion masses. Soft

ionization with minimal fragmentation in

combination with three readily available

reagent ions offers sufficient selectivity to

discern between most isobaric compounds,

for example trans-2-hexenal and furfural.

Of course, this selectivity is not ultimate,

such as with 2-methylbutanal and 3-meth-

ylbutanal, two isomers that could not be

discerned from each other.

Static Headspace SIFT-MS Analy-

sis: Static headspace analyses were

carried out with a CTC CombiPAL

autosampler (Thermo Fisher). The sys-

tem was installed on a TraceGC system

(Thermo Fisher), which was equipped

with a standard split–splitless injector

with a laminar cup liner. Due to the size

and weight of the SIFT-MS instrument

(900 × 725 × 875 mm, 212 kg), the

SIFT-MS system had to be placed on the

laboratory floor, close to the GC system.

Hyphenation was achieved by means of

the instrument’s heated external interface,

which entered the GC oven at the left-

hand side, similar to a regular benchtop

MS. The SIFT-MS and GC–MS instru-

ments were connected directly to each

other without any restriction installed in

the heated external interface, by means of

a piece of 5-m of deactivated fused-silica

capillary tubing (Siltek 0.25 mm i.d.,

Restek). During analysis, the split–split-

less injector, GC oven, and heated exter-

nal interface were kept at 200 °C. Carrier

gas was helium at 70 kPa, which corre-

sponded with a flow rate of 10 mL/min.

Injections were made in splitless mode.

Ungrounded malt grains (±5 g) were

placed in a 20-mL headspace vial, capped,

and subsequently placed on the autosam-

pler tray. A blank sample was prepared by

analyzing an empty vial (laboratory air).

All samples were equilibrated at 50 °C or

75 °C for 10 min. Afterwards, part of the

headspace was sampled by means of a gas-

tight syringe (2.5 mL, Hamilton, Reno,

Nevada) and transferred to the split–split-

less injector. Other headspace conditions

were set as follows: syringe temperature,

150 °C; agitation speed, 500 rpm; syringe

fill speed, 100 μL/s; injection volume, 2.5

mL; and injection speed, 10 μL/s.

Dynamic Headspace SIFT-MS Anal-

ysis: Volatile emissions from ungrounded

malt grains were sampled with a micro-

chamber–thermal extractor (μ-CTE,

Markes International, Llantrisant, UK).

The system consisted of six Siltek-treated

stainless steel sample containers (44 mL

capacity each), which could be sealed

from exterior air to prevent contamina-

tion from occurring. Usually, the micro-

chamber–thermal extractor is used as

a miniaturized alternative to carry out

material emission testing. Therefore, the

entire assembly is fed with a constant flow

of (inert) gas and brought to high tem-

perature (120 °C max). At the same time,

each active sample container is fitted with

a thermal desorption tube, which is filled

with an appropriate packing material to

enrich the released volatiles. Afterwards,

compounds are removed from the tube by

Methional

Benzaldehyde

Furfural

3-Methylbutanal

trans-2-Nonenal

Hexanal

2-Methylpropanal

Phenylacetaldehyde

2-Methylbutanal

Malt A

Malt B1

Malt C

Malt B2

Malt B3

Figure 3: Combined score/loading plot as the result of principal component analysis (PC1 versus PC2) displaying the differentiation of malt varieties (objects) on the basis of their volatile pattern targeted by headspace SPME GC–MS (variables).


means of thermal desorption or another

appropriate technique.

A schematic representation of the ana-

lytical set-up for volatile malt composition

analysis with the SIFT-MS instrument

and the microchamber–thermal extrac-

tor for dynamic headspace sampling is

depicted in Figure 1. Practical hyphenation

between both instruments was achieved

by connecting the SIFT-MS instrument

heated external interface with the outlet

of the microchamber–thermal extrac-

tor sample container. To achieve this, a

small piece of an empty thermal desorp-

tion tube was connected to the external

interface by means of a 1/4-in. nut and

ferrule. The metal frit, which normally is

used to secure the packing material, was

left in place to serve as a filter to prevent

small dust particles from entering the flow

tube. Contrary to the static headspace set-

up, the external interface was furnished

with an internal restriction to control and

reduce the flow towards the flow tube.

The restriction reduced the flow to 10

mL/min and simplified handling, which

permitted easy changeover from container

to container without vacuum disturbance.

A schematic drawing of the interface and

a representation when in use are given

in Figure 2. Approximately 25 g of malt

was used for analysis. During sampling,

the microchamber–thermal extractor was

kept at 50 °C, while the flow rate was set

at 10 mL/min (nitrogen). The total test

time was 20 min — 10 min equilibration

and 10 min actual data acquisition.

Principal Component Analysis: Prin-

cipal component analysis (PCA) was per-

formed for interpretation of the results

in a statistical way. PCA is a projection

method (bilinear modeling method) that

offers an interpretable overview of the

main information in a multidimensional

data table. The information carried by

the original variables is projected onto a

smaller number of underlying variables

(principal components). The first prin-

cipal component (PC1) covers as much

of the variation in the data as possible.

The second principal component (PC2)

is orthogonal to the first and covers as

much of the remaining variation as pos-

sible, and so on. The result of PCA is

displayed graphically to facilitate the

identification of patterns in data and

to detect interrelationships between

different variables.

In this study, PCA was used for differen-

tiation of the different malt samples on the

basis of particular compounds in their vola-

tile analytical pattern, which was obtained

by headspace SPME GC–MS and by

dynamic headspace SIFT-MS, respectively.

PCA was done by means of multivariate

data analysis software (The Unscrambler

v9.2, CAMO, Oslo, Norway).

Results and Discussion

Headspace SPME GC–MS Analysis:

Quantitative profiling of aldehyde mark-

ers was performed on all malt samples A,

B1, B2, B3, and C according to Vesely and

colleagues (19) by headspace SPME with

on-fiber PFBHA derivatization and capil-

lary GC in combination with a quadru-

pole mass spectrometer operating in the

single ion monitoring mode (m/z = 181;

see Experimental section). The investi-

gated aldehyde markers can be classified

into Strecker degradation aldehydes (2-

methylpropanal, 2- and 3-methylbutanal,

methional, benzaldehyde, and phenyl-

acetaldehyde), aldehydes formed during

Maillard reactions (furfural) and lipid

oxidation aldehydes (hexanal and trans-

2-nonenal). These compounds are to be

regarded as true markers for flavor insta-

bility of beer and are determined on a rou-

tine basis (32).

The quantitative results summarized

in Table II are the mean values of two

measurements with coefficients of varia-

tion situated between 0.2% and 25%.

The malted barley cultivar A has a rela-

tively low content of aldehyde markers

compared with the cultivars B and C.

Different crops from the same barley cul-

tivar B, referred to as B1, B2, and B3, vary

considerably in their aldehyde concentra-

tions. The aldehyde profile of variety C is

characterized by a high concentration of

3-methylbutanal and methional.

In order to visualize the differentiation

of the malt samples, the quantitative head-

space SPME GC–MS data were processed

with a multivariate data analysis software

package described earlier (CAMO). The

biplot as depicted in Figure 3 is the result

of PCA on the data matrix composed of

the different malt samples (objects) and

the measured volatiles (variables) in each

sample. The two first principal compo-

nents explain 94% (PC1 78%, PC2 16%)

of the total variance. Based upon their

volatile composition, the various malt

varieties A, B, and C are differentiated

clearly by means of PCA. Malt A was

characterized by the substantially lower

concentrations of the selected aldehyde

markers than were found for malt samples

B and C. Malt C is differentiated from the

other malt varieties by its higher amount

of methional present. From malt variety

B, harvest year B1 is distinguished from

B2 and B3 because lower concentrations

were measured for this crop.

On the basis of quantitative GC–MS

profiling of the selected aldehyde mark-

ers, clear classification of the malt sam-

ples was obtained by visualization of the

data matrix by PCA. To evaluate the

true potential of headspace SIFT-MS,

the headspace SPME GC–MS analyses

on the various malt varieties as described

earlier were repeated using this innovative

technique of real-time measurement. It

was verified by multivariate data analysis

that an equivalent differentiation of the

various malt varieties can be obtained

on the basis of their headspace profiles

acquired by SIFT-MS.

Static Headspace SIFT-MS Analysis:

Static headspace injection is by far the

easiest way for automated analysis of vola-

tile components by means of SIFT-MS. In

the first test to determine overall method

performance and sensitivity, malt type

A was analyzed. Therefore, ungrounded

malt grains were weighed into a headspace

vial, equilibrated and analyzed. In total,

17 carbonyl compounds were measured,

including the marker aldehydes deter-

mined by headspace SPME GC–MS.

As an illustration, the resulting SIFT-

MS trace for benzaldehyde after 10 min

equilibration at 50 °C is depicted in Fig-

ure 4. The results of the other compounds

are summarized in the bar graph in Fig-

ure 5. Compared to the blank analysis,

of which the results also are depicted in

Figures 4 and 5, only minor differences

can be discerned. To increase the response

of the target compounds, the extraction

temperature was increased to 75 °C (see

Figure 5). As expected, this led to a pro-

portional increase in signal intensity for

some of the volatile components, such

as acetaldehyde, hexanal, furfural, 2,3-

butanedione, 2-methylpropanal, 2-meth-

ylbutanal, and 3-methylbutanal. The per-

ceived response increase, however, is not

necessarily due to the elevated extraction

temperature alone, but also is affected by


the induction of oxidative processes and

heat load, which creates artifacts. To avoid

these oxidative reactions during analysis,

sampling temperature is, preferably, kept

as low as possible. As a result, static head-

space injection was not considered a valu-

able injection technique for the analysis of

aldehydes in malt.

Dynamic Headspace SIFT-MS Analy-

sis: When directly analyzing the headspace

of intricate samples such as malt, the sam-

pling technique used in combination with

SIFT-MS is of vital importance. Because

the static headspace analyses did not pro-

duce significant levels of target volatiles, the

experiment was repeated using dynamic

headspace SIFT-MS. Compared to the

static headspace procedure discussed ear-

lier, dynamic headspace extraction with

the microchamber–thermal extractor uses

a substantially higher amount of material

(25 g versus 5 g). As a result, higher absolute

responses are obtained easily without the

need to increase extraction temperature and

without inducing stress-related emissions.

Dynamic headspace SIFT-MS was

applied to the analysis of the target vola-

tiles in all malted barley samples. Figures

6 and 7 show qualitative data for the less

and more abundant volatiles, respectively.

Each result is the mean of two replicate

measurements with coefficients of varia-

tion situated between 0.5% and 15%. As

can be deduced from both figures, head-

space profiles clearly differ between malt

variety as well as harvest year. For example,

malt sample A is characterized by low lev-

els of aldehydes and other target volatiles,

and was received from the same malting

plant as malt samples B1, B2, and B3, but

produced from a different barley cultivar.

Depending on harvest year, the signal

intensity of the target compounds varied

substantially, as illustrated by malt samples

B1, B2, and B3. All originated from the

same barley cultivar, but from different

crops. Malt sample C was produced from a

different barley variety than A and B, and

malted by another malting plant, which

expressed itself in a dissimilar headspace

profile. Phenylacetaldehyde and benzalde-

hyde showed the highest signal intensities

in malt samples B1, B2, B3, and C. Obvi-

ously, malt sample A, which was character-

ized by only a limited number of abundant

compounds, shows the lowest signal inten-

sities for all detected volatiles. Knowledge

of these variations in headspace profiles

among various malted barley types, vari-

eties, and harvest years is of great interest

to many commercial users. Indeed, many

of these compounds are described in litera-

ture as key odorants in barley and malted

barley, and both the organoleptic quality of

beers and their flavor stability during aging

are affected by them (33–35).

The SIFT-MS results for the aldehyde

markers are in accordance with the head-

space SPME results earlier described.

To verify the grouping of different malt

Time(s)

Co

nce

ntr

ati

on

(p

pb

)

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220

14.5

14.0

13.5

13.0

12.5

12.0

11.5

11.0

10.5

10.0

9.5

9.0

8.5

8.0

7.5

7.0

6.5

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Kahosl_03-21216-2009-09-11-10-57-34.xml

Kahosl_03-21217-2009-09-11-11-15-12.xml

benzaldehyde (100-52-7)

benzaldehyde (100-52-7)

Figure 4: SIFT-MS trace of benzaldehyde after static headspace injection. Light blue trace shows the analysis of a blank sample (laboratory air); dark blue trace shows the analysis of malt A.

Sig

na

l in

ten

sity

40

35

30

25

20

15

10

5

0

2,3-Butanedione

2-M

ethylbutanal

2-M

ethylpropanal

3-M

ethylbutanal

(E)-2-H

eptenal

(E)-2-H

exenal

(E)-2-N

onenal

(E)-2-O

ctenal

(E)-2-Pentenal

(E,E)-2,4-D

eca

dienal

Acetaldehyde

Benzaldehyde

Form

aldehyde

Furfural

Hexanal

Methional

Phenylace

taldehyde

Blank

Static HS extraction 60 °C

Static HS extraction 75 °C

Figure 5: Volatile compounds targeted by static headspace SIFT-MS scans for malt type A.


varieties by PCA as was obtained with

headspace SPME GC–MS, the dynamic

headspace SIFT-MS data were processed

with the multivariate data analysis soft-

ware. To compare the results, the data

matrix for PCA was composed of only

the measured volatiles 2-methylpropanal,

2- and 3-methylbutanal, methional, benz-

aldehyde, phenylacetaldehyde, furfural,

hexanal, and trans-2-nonenal (variables) in

each of the malt samples (objects). Figure 8

represents the combined score–loading plot

(biplot). Based upon the headspace profiles

as acquired by SIFT-MS, this biplot bears

comparison with the PCA-plot as was

obtained previously from the headspace

SPME GC–MS results depicted in Figure

3. Next to a similar, significant classifi-

cation of the malt samples, Figure 8 also

displays good reproducibility of the SIFT-

MS results and exhibits that 95% of the

total variance is explained by PC1 (79%)

and PC2 (16%). The biplot in Figure 8

clearly visualizes the high potential of the

SIFT analysis for a fast classification of the

different malt samples on the basis of the

selected measured volatiles. Moreover, this

technique allows real-time measurement

of substantially more volatiles than is done

with headspace SPME GC–MS.

Conclusion

The objective of this study was to distin-

guish malt varieties on the basis of their

headspace profiles by means of headspace

SIFT-MS. A broad range of volatiles were

identified readily by direct analysis of

malt headspaces without sample prepara-

tion, derivatization, or chromatographic

preseparation. Cycle time per individual

sample could, therefore, be reduced to 10

min, which is substantially lower than the

more commonly applied technologies.

The results demonstrate the potential

of SIFT-MS for profiling different malts

on the basis of their volatile composition

(profiling) and for detecting the volatiles

associated with malt quality (quality con-

trol, cultivar selection).

Acknowledgment

Jo Vervenne (Interscience, Belgium) is grate-

fully acknowledged for providing the instru-

ment to perform the SIFT-MS experiments.

The authors are also grateful to Silke

Poiz (KaHo Sint-Lieven, Belgium) for per-

forming the headspace SPME GC–MS

experiments on the different malt samples.

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100

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60

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eca

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taldehyde

Form

aldehyde

Hexanal

Figure 7: Major volatile compounds targeted by dynamic headspace SIFT-MS scans for different malt types.


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van Donders, Eds. – Version 11.1.1 – Zeist

(The Netherlands): TNO Quality of Life

(1963–2009). ◾

Methional

Benzaldehyde

Furfural

3-Methylbutanal

trans-2-Nonenal

Hexanal

2-Methylpropanal

Phenylacetaldehyde

2-Methylbutanal

Malt A-2

Malt A-1

Malt B1-2

Malt B1-1

Malt B2-1

Malt B2-2Malt B3-2

Malt B3-1

Malt C-1Malt C-2

Figure 8: Combined score/loading plot as the result of principal component analysis (PC1 versus PC2) displaying the differentiation of malt varieties (objects) on the basis of their volatile pattern targeted by dynamic headspace SIFT-MS scans (variables).



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PRODUCT RESOURCES Ion-exchange columnsWaters’ Protein-Pak high-resolution ion-exchange columns are designed for the analysis of intact biomolecules including monoclonal antibodies, recombinant proteins, DNA/RNA, and vaccine components. According to the company, the column family consists of one anion-exchange (quatenary ammonium) column chem-istry and two cation-exchange column chemistries (a carboxy methyl and a sulfopropyl) each contained on monodisperse, nonporous particles. The multilayered network of ion-exchange functional groups on the particles reportedly results in high sample loading capacities for proteins not found with use of typical nonporous ion-exchange particles. Waters Corporation, Milford, MA. www.waters.com

UHPLC columnsMAC-MOD Analytical’s HALO Peptide ES-C18 columns are designed to deliver ultrafast, ultrahigh resolution separations with either UHPLC or conven-tional HPLC equipment. According to the company, the columns feature fused-core particles with specifically selected pore sizes and stable bonding chemistry for reliable peptide separations. The columns are available in column lengths as short as 30 mm and as long as 150 mm. MAC-MOD Analytical, Inc., Chadds Ford, PA. www.mac-mod.com

Carbonate removal deviceDionex’s Carbonate Removal Device 200 (CRD 200) is designed to remove carbon dioxide from the suppressed eluent stream by diffusion through the walls of a gas permeable membrane. According to the company, the device is available in three formats. The CRD 200 (4 mm) for removal from standard-bore systems, the CRD 200 (2 mm) for removal from microbore systems, and the CRD 200 (Capillary) for removal from capillary-scale systems at flow rates of 5–30 μL/min. Dionex Corporation, Sunnyvale, CA. www.dionex.com

UHPLC componentsIDEX’s UHPLC components include Upchurch Scientific’s Ultra-High Performance fittings rated to 20,000 and 30,000 psi, Sapphire Engineering’s UHPLC check valves rated to 30,000 psi, the Rheodyne TitanHT valve rated to 25,000 psi, and Isolation Technologies’ IsoBar column hardware rated to 20,000 psi. According to the company, these components increase the capability of separation systems and effectively handle the stresses of higher tem-peratures and system pressures. IDEX Health & Science, Oak Harbor, WA. www.idex-hs.com.

SPE systemFMS’ Powerprep SPE system combines SPE extraction and concentration into one step, is expand-able from one to six modules, and can run up to six samples simultaneously or 30 sequentially. According to the company, the system was designed to automate the manual steps of a laborato-ry’s sample preparation process by using a vacuum to load the sample quickly and a positive pressure pump to deliver sorbent volumes and flow rates. The system reportedly accepts all SPE cartridge and column formats. FMS, Inc., Watertown, MA. www.fmsenvironmental.com

Male HPLC nutsMicroSolv’s Better Male Nuts are designed with wide openings to ensure that the HPLC fit and seal remains in place longer, minimizing downtime of HPLC instruments. According to the company, the nuts feature both knurled and hex sections for starting by hand and final tightening using a wrench. The nuts reportedly can be used with PEEK or stainless steel standard HPLC tubing. MicroSolv Technology Corporation, Eatontown, NJ. www.mtc-usa.com

DetectorQuant’s NQAD detectors are designed to detect analytes including poor- and non-UV absorbing analytes, such as carbohydrates, polymers, detergents, anions, and cations down to subnanogram levels. According to the company, all models are suitable for UHPLC, HPLC, and SFC. An optional built-in fraction collector reportedly enables peak collection for further offline analysis and characterization. Quant Technologies, LLC, Blaine, MN. www.quant-NQAD.com

GC–MS systemThermo Fisher Scientific’s ISQ GC–MS system features a nonventing, full-source removal capability and the company’s ExtractaBrite ion source. The system is designed for simplified operation, and maximum uptime for use in applica-tions including forensics, toxicology, food safety, and environmental analyses. According to the company, the system offers a mass range of 1.2–1100 u and the ion source can be removed without venting the analyzer. Thermo Fisher Scientific, Inc., Waltham, MA. www.thermo.com


Sample preparation cartridgesDionex’s InGuard multiuse in-line sample preparation cartridges are designed for ion chromatography and are packed with a range of resins that automatically remove matrix interferences such as anions, cations including transition metals, and hydrophobic contaminants including lipids. According to the company, the cartridges can be used multiple times and are available in silver (Ag) form for the removal of halides; hydronium (H) form for the removal of polyvalent cations and neutralization of high pH samples; sodium (Na) form for the removal of transition metals and alkaline earth metals; hydrophilic reversed-phase (HRP) form for the removal of organic material; and a combined Na/HRP form. Dionex Corporation, Sunnyvale, CA. www.dionex.com

TubingAnalytical Sales & Services’ FlexChrom prefinished, one-piece flexible tubing is produced from a single piece of 1/16-in. o.d. stainless steel with the middle of the tube reduced to 1/32 in. o.d. to achieve greater flexibility. According to the company, the design of the tubing provides more strength at fitting connections. Analytical Sales & Services, Inc., Pompton Plains, NJ. www.analytical-sales.com

Gradient pumpSpark Holland’s SPH1240 ultrahigh-pressure gradient pump provides 500–18,000 psi at rates of up to 5 mL/min for the entire range of UHPLC analytical flow rates. Accord-ing to the company, the ergonomic design allows pumpheads to slide forward for easy access and connec-tion. An optional integrated degasser is reportedly avail-able along with extra solvent selection options for both pumps. Spark Holland, Emmen, The Netherlands. www.sparkholland.com

ADME systemBIOCIUS’ RF360 Hi-Res system for in vitro ADME analysis reportedly combines the accurate mass capabilities of an Agilent TOF-MS system and the high-throughput processing speeds of the company’s RapidFire system to eliminate lengthy method development for the analy-sis of metabolic stability, PAMPA, Caco, and other in

vitro assays. According to the company, the system features a streamlined workflow and has a processing rate of 10 s per sample. BIOCIUS Life Sciences, Inc., Woburn, MA. www.biocius.com

UHPLC columnsWaters’ ACQUITY UPLC BEH200, 1.7-µm SEC columns are designed for use with its ACQUITY Ultra-Performance LC (UPLC) system. According to the company, the combination of the SEC columns and UPLC system allows labora-tories to comply with U.S. Food and Drug Administration regula-tions that require firms developing and manufacturing therapeutic proteins accurately separate and quantify monoclonal antibodies (mAb) and their aggregates to ensure the efficacy and safety of a biopharmaceutical product. Waters Corporation, Milford, MA. www.waters.com

HPLC columnSupelco’s Ascentis Express Peptide ES-C18 HPLC columns are based on the company’s 160-Å Fused-Core particles. According to the company, this design exhibits very high column efficiency, providing a stable, reversed-phase packing with a pore structure and pore size that is optimized for reversed-phase HPLC separations of peptides and polypeptides. Supelco/Sigma Aldrich, Bellefonte, PA. www.sigma-aldrich.com

HPLC syringesHamilton Company’s GASTIGHT syringes are designed for use with Spark Holland HPLC autosamplers for dispens-ing liquid samples from a wide range of matrices and solvents. According to the com-pany, the polytetrafluoroethylene construction of the syringe plunger tip ensures a precise fit with the glass barrel, creating a leak-free seal. Hamilton Company, Reno, NV. www.hamilton.com

FluxerTheOX multiposition fluxer from Claisse is a fully automatic fusion instrument designed to prepare samples for XRF, AA, and ICP analysis. Accord-ing to the company, the instrument can reach tem-peratures up to 1200 ∘C and provide temperature control to ±1 ∘C. Claisse USA, Madison, WI. www.claisse.com


GC–MS detectorAgilent’s 5975T low thermal mass (LTM) gas chromatography–mass spectrometry detector (GC–MSD) is a transportable GC–MS system designed to deliver laboratory-quality analysis. According to the company, the detector was developed to be smaller, more rugged, and to con-sume less power than in-lab-oratory GC–MS instruments. Agilent Technologies, Inc., Santa Clara, CA.www.agilent.com

Microchannel plate detectorsPHOTONIS’ TruFlite microchannel plates and detector assemblies are designed for time-of-flight MS measurements. The plates’ input surface reportedly reduces uncertainty in ion arrival time, or time jitter, and surface flatness is measured and controlled. According to the company, the pore size and bias angle are optimized to improve mass detection. The microchannel plates and detectors are available with 18-mm and 25-mm active areas. PHOTONIS USA, Sturbridge, MA; www.photonis.com

Capillary GC systemThe GC-2010 Plus capillary GC system from Shimadzu includes a flow control system consisting of digital pressure control-lers, additional hardware, and software. Optional systems include a backflush system that discharges high-boiling-point components through the injec-tion port slit and a detector splitting system that splits com-pounds eluted from an analyti-cal column to multiple detectors. The GC system’s detectors include FID, FPD, ECD, FTD, and TCD systems, and a redesigned oven reportedly enables rapid heating and cooling. Shimadzu Scien-tific Instruments, Inc., Columbia, MD. www.ssi.shimadzu.com

Mobility instrumentWyatt’s Möbiuζ is a laser-based instrument designed for fast and reliable measurements of macromolecular electrophoretic and protein mobilities. According to the company, the instrument features parallelism of detection, extends the measurable molecular size range below 2 nm, and reduces measurement time to <60 s in most cases. Manual injection, an auto sampler, syringe pump, or an auto titrator can be used to introduce samples. The system reportedly has temperature control capability and can perform automated temperature studies. Wyatt Technology Corporation, Santa Barbara, CA. www.wyatt.com

Ion-trap mass spectrometerBruker’s amaZon SL ion-trap mass spectrometer is designed to increase analytical capabilities and productivity for labora-tories involved with detailed structural analysis of all types of molecules. According to the company, the system features automated and intuitive soft-ware, a fast data acquisition speed at full isotopic resolution in both MS and MS-MS for use with UHPLC, on-the-fly polarity switching for analysis of a diverse set of compounds, and optimal, highly reproducible fragmentation efficiency to help identify unknown compounds. Bruker Daltonics, Inc., Billerica, MA; www.bdal.com

Water purification accessoryMillipore’s Q-POD Element unit is designed for use with the Milli-Q Integral and Milli-Q Advantage systems to deliver ultra-pure water with sub-part-per-trillion levels of elemental contamination for laboratories performing trace and ultratrace elemental analysis. According to the company, the device eliminates problems due to back-grounds with high elemental contamina-tion and can be used to provide water for blanks, standard solutions, sample dilutions, and plasticware rinsing. Millipore Corporation, Billerica, MA.www.millipore.com

AutosamplerCTC Analytics’ PAL HPLC-xt series autosampler is designed to increase precise and accurate sample loading and throughput. According to the company, the system features fast cycles, mod-ular architecture and flexibility, near zero carryover, and a syringe that acts only as an aspirator and dispenser device. The sample reportedly is no longer in contact with the syringe, but is aspirated into a holding loop instead. CTC Analytics, Zwingen, Switzerland. www.palsystem.com

Quaternary pumpThermo’s Accela 1250 quaternary pump is designed to operate at a top pressure of 1250 bar with flow rates of up to 2 mL/min for use in separat-ing complex mixtures, such as red wine, during UHPLC analysis. According to the company, the pump features a feedback control system that eliminates the need for pulse dampening and improves flow accuracy and gradient precision under extreme oper-ating conditions. Thermo Fisher Scientific, Inc., San Jose, CA. www.thermo.com/lc


UHPLC systemShimadzu’s Nexera UHPLC system features high-speed and high-resolution analysis, near-zero carryover, good linearity, and precision and is designed for micro LC, conventional LC, UHPLC, and LC–MS applications. According to the company, the system can perform analyses at pressures up to 130 MPa and features an injection time of 10 s, greater than 4600 sample capacity, and fixed-loop injection. Shimadzu Scientific Instruments, Inc, Columbia, MD.www.ssi.shimadzu.com/nexera

Chiral screening servicePhenomenex’s Chiral Screening Service is designed for customers in pharmaceutical and natural products research and development. According to the company, the free ser-vice provides target screening using a library of HPLC and SFC columns, including its Lux polysaccharide-based columns, which reportedly demonstrate a success rate of nearly 90%. After resolving the chiral compound, the company also reportedly produces method development and optimization for the customer within 10 business days. Phenomenex, Inc., Torrance, CA. www.phenomenex.com

MicroplatesMicroLiter’s microplates for chromatography are available in 2-mL square, deep well, round, and conical bottom; 1.3-mL round well round bottom; and 0.75-mL round medium well round bottom designs. According to the company, the microplates feature clear polypropylene for visual reference of samples and have pierceable covers in either EVA or silicone with sprayed on PTFE barriers. MicroLiter Analytical Supplies, Inc., Suwanee, GA. www.microliter.com

UHPLC–MS columns Optimize Technologies’ hand-tight OPTI-TRAP EXP trap columns are sample purification and precon-centration products designed for use at pressures as high as 20,000 psi (1400 bar). According to the company, the columns can connect directly to any injection valve (with 10–32 threads) or in-line with the company’s OPTI-LOK EXP fittings. Optimize Technologies, Inc., Oregon City, OR.www.optimizetech.com

GC columnsThermo’s TraceGOLD GC capillary columns are designed to provide run-to-run and column-to-column reproducibility and ultralow bleed for consistent, reliable data and extended column life. According to the company, the columns are inert to ensure the best peak shapes and low baseline noise and provide improved limits of detection with enhanced resolution of low-level analytes. Thermo Fisher Scientific, Inc., San Jose, CA. www.thermo.com/columns

Capillary tubing cleavingPolymicro reportedly has expanded its capabilities for cleaving and cutting its polyimide-coated fused-silica capillary tubing. According to the company, the new devices provide laser cutting and polishing of small-i.d. capillary tubing. Polymicro Technologies, a subsidiary of Molex, Incorporated, Phoenix, AZ. www.polymicro.com

LC–MS systemAgilent’s 6150B series single-quadrupole liquid chromatograph–mass spectrometer is designed to provide higher sample throughput and can scan at 10,000 amu/s. According to the company, the system’s sample inlet design uses superheated sheath gas to focus the ion stream entering the mass spectrometer, which provides a stronger signal with lower standard deviation at the limit of detection. The ionization technique reportedly enables efficient ionization for a broader range of com-pounds than electrospray or atmospheric pressure ionization alone. Agilent Technologies, Inc., Santa Clara, CA. www.agilent.com

HILIC columnsSeQuant ZIC-HILIC columns from EMD Chemicals and Merck can be used in the recommended LC–MS-MS analysis method in the FDA’s Pharmaceutical Industry Guidance on Pre-venting Melamine Contami-nation in Pharmaceuticals and for the Melamine and Cyanuric Acid screening method in food. Accord-ing to the company, the method is superior to alternative measurement methods for analyz-ing food contaminated with melamine as well as other toxic triazine compounds. EMD Chemicals, Gibbstown, NJ. www.emdchemicals.com


Literature

Sample preparation catalogBiotage has published a 176-page sample preparation catalog that includes a range of products for bioanalytical, forensic, clinical, environmental, agrochemical, and food applications. According to the company, the catalog fea-tures an application index with links, comprehensive information to assist with using the products, and a product selection guide. Biotage, Uppsala, Sweden. www.biotage.com

BrochureHitachi has published a brochure titled “LaChromUltra: Ultra High-speed Liquid Chromatograph Application Data.” The 28-page brochure features applications for pharmaceuticals, cosmetics, foods, environmental com-pounds, and chemicals. All separations were performed using the LaChromUltra instrument. Hitachi High Technologies America, Inc., Schaumberg, IL.www.hitachi-hta.com

Application noteOI Analytical has published a 32-page application note with information on the U.S. EPA’s Method 524.3 for GC–MS analy-sis of volatile organic compounds in drinking water. According to the company, the note provides comprehensive method valida-tion data and explanations of changes to instrumentation operating parameters permitted in this method. OI Analytical, College Station, TX. www.oico.com

Metabolomics libraryLECO has published a full-color flyer about its LECO/Fiehn Metabolomics Library. The library features more than 1100 spectra of 700 unique metabolites along with retention indices based on a series of fatty acid methyl esters. According to the company, the flyer highlights the benefits of the library, provides ordering informa-tion, and shows how library data are displayed on screen. LECO Corporation, St. Joseph, MI. www.leco.com

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Malt Profiling with SIFT-MS