News from the ACS National Meeting: Why genomics is not enough

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During DNA transcription, RNA polymerase(RNAP) molecules tend to move discontinu-ously, pausing at various sites before impor-tant transcription events. Until recently, mostexperiments into the dynamics of DNA tran-scription have relied on studies of bulk com-plexes halted by nucleotide starvation to pro-vide a snapshot of RNAP activity. Because thesetypes of studies involve large numbers of DNA molecules, some details are averaged out.Carlos Bustamante and co-workers at the University of California–Berkeley, the Uni-

versity of Wisconsin–Madison, and Lawrence Berkeley National Laboratory now reportthat they have directly observed transcription pausing and arrest activity by E. coli RNAP.The researchers began by tethering a single DNA molecule between two streptavidin-coated, 2.2 µm polystyrene beads. One bead was mounted on a glass pipette tip, and theother was held in a laser optical trap. The researchers controlled the tension on the DNAstrand by varying the flow of fluids past the beads and manipulating the trapping laser.Because DNA contracts when RNAP is actively transcribing, the researchers can recordRNAP dynamics by monitoring the distance between the beads with a video microscope.Bustamante’s group studied transcription as a function of the surrounding solution con-ditions and the tension applied to the DNA strand. (Science 2000, 287, 2497–2500)

Schematic of RNAPtranscription of DNAtethered betweenpolystyrene spheres.(Adapted with per-mission. Copyright2000 AmericanAssociation for theAdvancement ofScience.)

Swell hydrogel devices

Some polymer hydrogels display dra-matic, reversible volume changes inresponse to stimuli, such as varyingtemperature, pH, or electric fields.The phenomenon has led researchersto create hydrogel actuators, whichare sometimes described as artificialmuscles. Unfortunately, the timerequired for a hydrogel to expand orcontract is often slow, ranging fromtens of seconds to minutes. In gener-al, the response time increases in pro-portion to the system size. So whynot go small?David Beebe and co-workers at

the University of Illinois at Urbana–Champaign and the University ofWisconsin–Madison used microlitho-graphic techniques to pattern minia-ture hydrogel actuators for controllingthe flow of liquids in submillimeterchannels. In one configuration, thepH of the working fluid determinedthe hydrogel valve settings, sendingacids in one direction and bases in

another, and shutting off completelyat pH 6.7. In another setup, a controlfluid operated a valve that was sepa-rated from the working fluid by a thinmembrane. Actuation times were only

seconds due to the minuscule scalesof the hydrogel structures, whichmay lead to novel biosensors anddrug delivery systems. (Nature2000, 404, 588–590)

ANALYTICAL CURRENTS

Polymer hydrogel pillars swell in response to pH changes, regulating liquid flow. (Adaptedwith permission. Copyright 2000 Nature Publishing Group.)

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New methods for detecting SalmonellaBad food requires good analytical science.

Unfortunately, detecting the food- and

waterborne pathogen Salmonella quickly

and with high sensitivity is not easy. Two

new approaches may change that.

The first comes from the laboratory of

Wilfred Chen and colleagues at the Uni-

versity of California–Riverside, who used

real-time PCR with molecular beacons.

This method is relatively fast (finished

within several hours, not days), very

sensitive, and has the potential to quan-

tify the amount of bacteria.

Molecular beacons are fluorescently

labeled, folded fragments of single-

stranded DNA that unfold when they

hybridize to their target. The fluorescent

label is attached to one end of the

molecular beacon, and a quencher is

attached to the other end. Thus, when

the beacon is folded, the quencher is

near the label, and the beacon is “dark.”

If the beacon unfolds, the quencher

moves away from the label, and the bea-

con “lights up.” Combining molecular

beacons with real-time PCR technology

allows researchers to monitor the accu-

mulation of the product.

In this case, the researchers designed

molecular beacons to recognize a 16-

base-long region of the himA gene of Sal-

monella. Seven Salmonella strains were

analyzed, and all produced strong fluo-

rescent signals after 40 rounds of amplifi-

cation. Detection limits as low as two

colony-forming units of bacteria per

reaction were achieved. In addition, the

linear relationship between the critical

cycle—a parameter that indicates when

the fluorescent signal becomes strong

enough to detect—and the initial amount

of DNA in the reaction suggested that the

assay could quan-

tify the amount of

Salmonella. (Anal.

Biochem. 2000,

280, 166–172)

An alternate

approach is

described in an

upcoming issue of

Analytical Chem-

istry (available

on the Web at

http://pubs.acs.

org/ac) by Akira Takeuchi and Koji Sode

at Q. P. Corp. and Tokyo University of

Agriculture and Technology (both in

Japan). In their method, some cells are

taken from a food sample, and PCR is

used to amplify the oriC sequence,

which is where replication of the chro-

mosome begins in Salmonella and other

bacteria. However, unlike other PCR-

based methods, the specificity is not

determined solely by PCR primers and

probes. And unlike hybridization-based

microarray techniques, the new method

does not require an additional denatura-

tion–annealing step.

Instead, the researchers use a DNA

binding protein called DnaA to detect

the double-stranded PCR product from

Salmonella. DnaA’s normal role is to bind

to oriC and help initiate and regulate

replication. In particular, the 94-amino-

acid, C-terminal segment of DnaA, called

Domain IV, binds to the “DnaA box”—

a fragment of oriC that consists of four

or five repeats of a specific 9-base

sequence. This binding occurs with a

high degree of specificity.

For convenience, DnaA domain IV

can be expressed as a fusion with a glu-

tathione S-transferase tag, which allows

the fusion protein to stick to a gel matrix

bearing glutathione. If the PCR products

are then incubated with this gel, the oriC

fragments from Salmonella will be cap-

tured. Any unbound PCR products are

washed away. Finally, the intercalating

dye SYBR Green I labels the captured

DNA fragments, and fluorescence meas-

urements are taken.

When the method was tested, the

researchers found that a sequence from

Citrobacter sp. and a sequence from E.

coli ATCC10536 were amplified along

with oriC from Salmonella. However, the

DnaA binding protein captured only the

fragment containing oriC.

To detect Salmonella, the DnaA box (rectangle), which is withinthe oriC sequence, binds to DnaA IV, a specific domain of theDNA binding protein (speckled crescent). DnaA IV is attachedto a gel matrix using the glutathione S-transferase tag.


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Aptamers getrecognition

Are aptamers the nextbig strategy for identify-ing biologically impor-tant ligands? These nu-cleic acid species seemto change conformationwhen bound to a ligand,demonstrating that anattached fluorophorecould signal bindingbecause of changes inits local environment.Moreover, aptamers areeasily synthesized withdyes attached to specificlocations.Andrew D. Ellington

and colleagues at theUniversity of Texas–Austin, Indiana Univer-sity, University of Michi-gan, and University ofFlorida describe theaddition of fluorophoresto various sites on twoanti-adenosine aptamers,

one made from RNA and the other from DNA. The bestsignaling aptamers increased fluorescence intensity by25–45% in the presence of as little as 1 mM ATP. Fluores-cence varied with ATP concentration, but it changed littleor not at all when the adenosine in ATP was replaced byguanine. Response curves were reproducible, but they didnot fit simple binding models based on the reported val-ues for the aptamers. Further study revealed that theaptamer contains two binding sites, accounting for theunexpected response curve. (J. Am. Chem. Soc. 2000,122, 2469–2473)

Remote NQR spectroscopyNuclear quadrupole resonance (NQR) spectroscopy was apopular technique for studying nuclei in the 1950s, but eventu-ally it was eclipsed by NMR spectroscopy. G. V. Mozjoukhineand V. P. Anferov of Kaliningrad State University (Russia) andR. Fisher of SEE Corp. (Australia) are among the researchersreconsidering the technique for remote detection of the com-pounds in illegal narcotics and plastic explosives. In particu-lar, they believe NQR may help to locate antipersonnel land-mines that threaten civilian populations in the world’s manywar-torn regions. Such landmines often contain only smallamounts of metal and are difficult to track down with conven-tional metal detectors.

Both NMR and NQR involve the observation of nuclearenergy level transitions induced by radio-frequency electro-magnetic fields. Whereas NMR requires an external magneticfield to generate energy differences between nuclear spinstates, NQR relies on coupling between the nuclear electricquadrupole moment and the local electric field gradient. Thus,NQR can remotely detect materials because external magnetsare unnecessary.

Mozjoukhine’s group has built a pulsed NQR spectrometertailored for detecting explosives and narcotics under real-world conditions. The researchers demonstrated the approachby detecting a model landmine, consisting of 150 g of explo-sive in a plastic box, at a distance of 22 cm by combining NQRspectrometry with digital signal processing and custom detec-tion circuitry. Although the feat required 81 s to complete, theresearchers predict that, under some circumstances, detec-tion times could be decreased to as little as 2 s. (Rev. Sci.Instrum. 2000, 71, 1656–1659)

Despite the popularity of self-assembled

monolayers, many of the details of how

they form are still unknown. This can

lead to surprises when building mono-

layers. For example, because of kinetic

restraints, the surface film composition

of a mixed monolayer film may not

reflect the mole fractions of the compo-

nents in solution that are used to pre-

pare it.

R. Georgiadis and co-workers at

Boston University use two-color surface

plasmon resonance (SPR) spectroscopy

to study the sequential kinetics leading

to the formation of a two-component

film, which consists of a 25-mer single-

stranded DNA functionalized with a pen-

dant (CH2)6SH at the 5´ position and a

diluent mercaptohexanol. The thiol-mod-

ified DNA was bound to a gold surface,

Kinetics of monolayers

Some of the sites used for incorpo-rating dyes into the DNA aptamerare marked in yellow. Boundadenosines are shown in purple.


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which is then probed by SPR. They also

investigated the subsequent hybridiza-

tion of the surface-attached DNA with

complementary DNA.

Each kinetic step leading to formation

of the surface film could be modeled

quantitatively with a simple physical

model that accounts for the simultane-

ous adsorption, desorption, and diffusion

of absorbate molecules. Moreover, the

kinetics of formation and subsequent

DNA hybridization follow remarkably

similar kinetic pathways. However, the

adsorption of unmodified ssDNA on a

gold surface demonstrates a complex

behavior involving multiple kinetic steps.

This indicates that kinetic isotherms

from quantitative SPR can distinguish

between different types of adsorbate/

surface interactions. (J. Am. Chem. Soc.

2000, 122, 3166–3173)

Detecting signals that route proteins

Moving proteins in and out of thenucleus is a normal part of the cell’sbusiness, and it is critical for the liveli-hood of many pathogens that infectcells. Larger proteins rely on sequencescalled nuclear localization signals(NLSs) to direct them to the nucleusand, conversely, nuclear export sig-nals (NESs) to exit the nucleus.Both NLSs and NESs areshort sequences, and thereis little consistency amongthe sequences, makingthem very difficult toidentify.Now, Vitaly

Citovsky and col-leagues at the StateUniversity of NewYork–Stony Brook, theAgricultural ResearchOrganization (Israel),and SmithKline BeechamPharmaceuticals (U.K.)describe an assay for NLSsand NESs that is based on thereporter b-galactosidase, whichis encoded by the lacZ gene.This assay depends on the fusion

of three DNA sequences: a modifiedversion of the bacterial gene lexA, theactivation domain of the yeast geneGAL4, and the gene of interest. If thegene of interest contains an NLS,then the triple fusion protein willenter the cell’s nucleus. There, theLexA sequence will direct the fusionprotein to a region of the lacZ gene

that controls expression, and theGal4p sequence will activate expres-sion of b-galactosidase. The cell will

then turn blue. As a backup, the pres-ence of an NLS will, through a simi-lar mechanism, allow the cell to begrown on media that does not con-tain histidine; thus, histidine-deficientmedia will eliminate any cells that lackan NLS. The researchers confirmedthe system’s performance usingthe VirD2 protein from Agro-bacterium, which contains aknown NLS.

A similar system wasdesigned to test forNESs. In this case, theNLS from the virusSV40 was placedbetween the lexA geneand the GAL4 activa-tion sequence. Theaddition of the NLSensures that a proteinwill be imported intothe nucleus unless anNES is present. Thus, thedefault is that cells will turnblue and grow on histidine-

deficient media, and the pres-ence of an NES reverses that. The

researchers used this assay to demon-strate, for the first time, that the pro-tein that encapsulates the tomato yel-low leaf curl virus has an NES. Theresearchers note that the advantage ofthese two assays is that they rely onthe function of the NLS and NES,not just the presence of a putativesequence. (Nat. Biotechnol. 2000,18, 433–437)

Schematic of the NLS and NES fusion proteins.In the NLS assay, the modified LexA sequencecomes first, followed by the Gal4p activationdomain, and the protein of interest. In the NESassay, the NLS from the virus SV40 is insertedafter the LexA sequence. (Adapted with per-mission. Copyright 2000 Nature America.)


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When Michael Beverly set out insearch of an MS method to analyzebacteria for his doctoral thesis at theColorado School of Mines (CSM), heinitially settled on electron capturenegative ion (ECNI) MS for liberat-ing the compounds characteristic ofspores from anthrax and other bacte-ria. The technique readily identified

dipicolinic acid (m/z 167), a sub-stance that comprises up to 15% ofthe dry weight of some bacteria in thedormant, sporulated state. As is typi-cal of ECNI MS spectra, however,background signals from numerousother compounds tended to interferewith the dipicolinic acid signature. Atthe suggestion of his advisor, KentVoorhees, Beverly repeated his experi-ments with an ionization techniquerecently revived at Oregon State Uni-versity. To Beverly’s delight, the elec-tron monochromator (EM) MS essen-tially eliminated spectral interferences,clearly distinguishing the dipicolinicacid peak even from other ions withthe same m/z ratio.Electron monochromators, which

produce narrow bandwidths of low-energy electrons, have been usedsince the 1950s to study ionizationpotentials of rare gases and electroncapture resonances for various mole-cules. But it wasn’t until the early1990s, when James Laramee andMax Deinzer at Oregon State Uni-versity and Robert Cody of JEOL

USA developed sourcesthat could produce hun-dreds of microamps, thatthe devices became practi-cal for analytical chemistry.Because electron captureionization is a resonantprocess, ionization withmonoenergetic beams pro-vides an added level ofspecificity that is beyondthe capabilities of chemicalionization schemes, whichproduce a range of ionizingelectron energies.Beverly is hard-pressed

to imagine a situation inwhich traditional ECNI MSanalysis might be preferableto monochromator ioniza-tion. “Maybe if you haveno a priori knowledge of

your electron capture energy,” specu-lates Beverly, “you could hit yoursample with a broad spectrum ofenergies produced with a regularECNI source.” Although, Beverlypoints out, scanning the electronenergies with a monochromator pro-vides the same result with an extradimension of data due to the addi-tional electron capture information.In this issue of Analytical Chemistry(pp 2428–2432), Voorhees and Bev-erly join with Cody and Ted Hadfieldof the Armed Forces Institute ofPathology in focussing specifically onbacterial studies, but numerous otheranalyses are amenable to the tech-nique. For example, EM MS can dis-tinguish between product ions of the

explosive TNT and nitrobenzene, acommon component of many benigndomestic products. A similar featwould present significant challengesto conventional ECNI MS systems.According to Laramee, who is now

a principal chemist with MidwestResearch Institute in Kansas City,MO, “One of the problems withECNI MS is that you have to put amoderating gas in the source to ther-malize the electrons,” leading to acomplex plasma of neutral molecules,positive ions, negative ions, and reac-tive radicals from both the analyteand the buffer gas. ECNI mass spec-tra are highly sensitive to conditionsin the source; ion ratios vary fromone device to another and often fluc-tuate even in a single machine.Though EM MS also benefits frommoderating gases that help preventelectrons from spontaneously detach-ing from negative ions, eliminatingthe role of moderators in coolingelectrons allows researchers to choosegases, such as CO2, which interferewith spectra to a significantly lesserdegree. It’s even possible to makedue without a moderator gas in EMMS, simplifying the source design atthe expense of slightly lower production currents.In addition to bacterial studies,

Voorhees’ group at CSM will soonbegin analyzing components of dieselexhaust. Voorhees is confident thatEM MS could benefit nearly anyanalysis that is currently performedwith ECNI spectrometers. In particu-lar, electron capture energy informa-tion will ease the challenge of distin-guishing between product ion iso-mers. The comparatively simple ionsource is attractive for field-portabledesigns that may eventually monitorfor a range of substances, includingbacteria, explosives, pesticides, andchemical warfare agents.

James Riordon

Adding dimensions to MS with electron monochromators

SCIENCE

Electron monochromator schematic.


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NEWS FROM THE ACS NATIONAL MEETING

Elizabeth Zubritsky reports from San Francisco, CA

Measuring insulin secretionfrom single cells

In type 2 diabetes—the most common form—the body makes

insulin, but it is not effective, so the blood sugar level rises.

Many researchers think that the insulin does not get released

properly, but the coupling of impinging stimuli and insulin

release are not well understood. Now, Robert Kennedy and

colleagues at the University of Florida have developed a fluo-

rescence microscopy method that can reveal insulin secretion from single cells with spatial and temporal resolution.

The researchers had previously used amperometry for direct detection of insulin release from individual b-cells. In a recent

application of this method, they showed that the presence of insulin

outside a cell could trigger the release of more insulin. Other research-

ers had identified insulin receptors on the surface of b-cells, but no

one had linked them to this physiological effect before.

However, amperometry is limited because the microelectrodes are

single-point sensors. To get high spatial and temporal resolution, the

researchers switched to fluorescence microscopy. Because they can-

not easily measure insulin fluorescence, they monitor Zn2+ secretion

instead, using the fluorescent dye Zinquin (Anal. Chem. 2000, 72, 711–

717). Zn2+ is stored along with insulin in the secretory vesicles inside

the b-cell. When the vesicles fuse with the cell membrane, they

release the Zn2+–insulin complexes outside the cell. The complexes

dissociate, leaving Zn2+ free to bind with Zinquin.

Kennedy and colleagues saw that Zn2+—and by extension, insulin—

is only released from one region of the cell. Why? The researchers note

that b-cells are arranged in rings around blood vessels, and they spec-

ulate that this polarity may ensure quick delivery of insulin to the blood-

stream. By imaging Zn2+ and Ca2+ simultaneously, the researchers also

found that Zn2+ is released in the same region where Ca2+ first enters

the cell. Ca2+ eventually enters all over the cell, but the correlation

between the site of the initial Ca2+ uptake and the site of Zn2+ release

suggests that the Ca2+ entry sites are coupled to the active secretion

zone in these cells.

Why genomics is not enough

The human genome may provide the best evi-dence yet that by gaining knowledge, we beginto realize how little we know. As the sequencenears completion, we hear more comments thatthis data alone will not answer all of our ques-tions about human development and disease. Infact, Bill Hancock of Agilent Technologies saidthat more people are now paying attention tothe so-called epigenetic model, which holds that“the genome [itself] is essentially featureless.You only get information out of it when youstimulate a pathway.”In a talk advocating the integration of

genomics, proteomics, and metabolic studies,Hancock made a simple, yet profound andoften overlooked, point: Studies of gene expres-sion often assume that the concentration ofmRNA is equal to, or at least proportional to,the concentration of protein. But this is notnecessarily true. Citing a paper that found apoor correlation between the amount of mRNAand the amount of protein in samples takenfrom 60 human cell lines (Anderson, N. L.;Anderson, N. G. Electrophoresis 1998, 19,1853–1861), Hancock argues that mRNA andprotein levels are not necessarily proportional.However, many researchers have preferred toassume a straightforward relationship, he said,but they must now confront the fact that somecases may be considerably more complicated.

Montage of images showing Zn2+ release. The images show twocells touching each other, which explains the oblong shape. Thered color indicates where Zn2+ is being released. (Seehttp://pubs.acs.org/ac for a movie of Zn2+ release.)


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HPLC looks for orthogonaltechniques

In the pharmaceutical industry, themethod of choice for determiningimpurities in a drug is most oftenreversed-phase HPLC. Yet, guidelinestypically request the confirmation ofsuch analytical methods by anothertechnique or “orthogonal” procedurewith totally different selectivity.Nebojsa Djordjevic of Novartis

Pharma (Switzerland) has been usingpacked capillary electrochromatographyas an orthogonal technique, althougha suitable commercial instrument isnot yet available. Usually, gradientseparation is necessary, and this canbe performed most easily by a fasttemperature increase during the chro-

matographic run (e.g., 25–60 °C at3 °C/min). There are still numerouspractical problems to overcome, saysDjordjevic, such as designing frits thatdo not lower the separation perform-ance, developing robust stationaryphases that provide a broader pH andselectivity range, and improving col-umn-to-column reproducibility.Meanwhile, Christoph Siffrin, also

of Novartis, uses supercritical fluidchromatography (SFC) in packedcolumns as an orthogonal technique.Even highly polar compounds, suchas the salts of drug substances, can beseparated under normal-phase SFCconditions. The separations are muchfaster than with HPLC, he says.Roger Smith of Loughborough

University (U.K.) advocates chro-

matography with superheated water.This approach is orthogonal to HPLCwith C18 and similar columns, becausethese silica-based stationary phases arenot stable in water at temperatures ashigh as 200 °C. Smith uses insteadstyrene-divinylbenzene, polybutadi-ene-coated zirconia, or graphitic car-bon phases. Water as a mobile phaseis environmentally friendly and cheap.UV detection at wavelengths as lowas 190 nm is easily possible, as well asthe opportunity to couple MS andNMR (with D2O) or use of severalGC-type detectors with the instru-mentation. So far, a broad variety ofanalytes such as phenols, aromaticamines, various classes of drugs, andplant extracts have been successfullyseparated, says Smith.

Veronika Meyer reports from Munich, Germany.

Sandia introduces lab-on-a-chip prototype

For several years, Sandia National Laboratories has been developing a portable chemical analysis system, fabricated usingmicroscale techniques, called µChemLab. Bits and pieces of the device have been presented previously. Now, a handheldresearch prototype has arrived.Christopher Bailey described this initial prototype, which is a modular dual-phase chromatography system intended for

the detection and analysis of chemical warfare agents. The LC module, meant for detecting explosives, has two columnsand can perform open-cell CE. Analysis takes only ~1 min, and detection of analytes at the part-per-billion level is possi-ble using an indirect laser-induced fluorescence detection system with a ~0.5 cm 3 0.5 cm footprint. This system uses

high-efficiency vertical cavity surface-emitting lasers, which arebonded onto the substrate, and the diffractive optics are etchedinto the substrate. The focusing optics, interference filters, anddetector are mounted off the module.The GC module, meant for detection of chemical agents,

such as sarin and mustard gas, uses sol–gel absorbents to pre-concentrate the samples. Separations are carried out in a 2-m-long spiral channel that has been cut into a 1 cm2 area usingdeep ion etching. Analysis takes ~30 s, and detection isachieved with a surface acoustic wave detector (Anal. Chem.1998, 70, 775 A).Future versions of µChemLab will incorporate additional

modules and capabilities, including on-chip HPLC—madepossible by the high-pressure electrokinetic pumping tech-nique that can route liquids through the microscale channelswithout any moving parts (Anal. Chem. 1998, 70, 776 A).Future instruments are also expected to be more fully inte-grated than the current prototype and able to detect bothbiological and chemical warfare agents.

Sandia National Laboratory’s prototype of the handheld chemicalanalysis system called µChemLab.

NEWS FROM ANALYTICA 2000


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NACLA gains momentum

The National Cooperation for Laboratory Accreditation (NACLA)announced at its second annual general meeting in April that efforts toreduce the number of accreditations for U.S. testing and calibrationlaboratories are well underway. Although participation is still lowerthan organizers had originally hoped, membership in NACLA reached100 in January.Any organization that has an interest in laboratory accreditation in

North America can apply for membership in NACLA in one of thefollowing capacities—accreditor, government, laboratory, user ofaccreditation or laboratory services, or general interest. Membershipin NACLA, however, does not guarantee recognition as a NACLAaccrediting body. All accreditors will be evaluated according toNACLA recognition procedures.Thus far, four applications have been received from accrediting bod-

ies, two of which had already undergone evaluations at the time ofthe meeting, and four more accrediting bodies are working to com-plete their applications. Recognition of the first group of accreditingbodies is expected this month.NACLA is a public–private partnership aimed at providing single

Is yourT-shirt toxic?

Some azo dyes can release carcinogenicamines after reductive cleavage of the azobond. An example is acid red 114, which,following reduction, breaks down to o-toli-dine (3,3-dimethylbenzidine). In Germany,these type of azo dyes are banned, and thetoxic amines from the degradation productsmust not exceed 30 mg/kg of textile.Pakawadee Sutthivaiyakit of the Kasetsart

University (Thailand) described an LC/MS/MSmethod with atmospheric pressure chemicalionization for the quantitative analysis of 20of these unwanted amines. The research wasdone at the GSF National Research Centerfor Environment and Health (Germany) withStefan Achatz and Antonius Kettrup. Textilesample extracts were reduced with sodiumdithionite and cleaned using solid-phase ex-traction (following an official procedure) orwith liquid–liquid extraction, which is a sim-pler process. One of the goals of methoddevelopment was to obtain short total analy-sis times, and, therefore, the LC separationwas performed on short columns in an isocrat-ic mode. Peaks do overlap, says Sutthivaiyakit,but multireaction monitoring MS/MS allowsselective detection of the compounds.In quadrupole mass spectrometer 1, a

characteristic precursor is selected, thenfragmented in quadrupole 2 by collision,and finally, the most abundant fragment isselected by quadrupole 3. This MS approachis limited to eight compounds at a time.Therefore, each sample extract undergoesthree consecutive chromatographic runswith different MS conditions. Nevertheless,the total LC/MS/MS analysis time for allthree runs is less than 15 min. For example,o-tolidine is identified by its retention timeof about 4.5 min and characteristic ions atm/z 213, which is the precursor [M+H]+ ion,and m/z 196, which is the product ion afterloss of NH3. Other toxic amines identified inthis manner include benzidine, 2,4-diamino-toluene, 4,49-thiodianiline or 4-chloro-2-methylaniline.Sutthivaiyakit plans now to establish the

procedure at her university. Thailand has abig textile industry, and an efficient controlof goods produced for export is of utmostimportance.

Academic quality management

Quality managers at a research center or in a university have a hardertime than their colleagues in industry. In industry, there are clearguidelines or even government regulations on the analyses of com-mercial products. But what about analyses that are performed forinternal clients or for a research project?Markus Krapp of the GKSS Research Centre (Germany) has found

a way to establish a quality regimen at his institution. Some, but notall, laboratories and several individual procedures of the Centre areaccreditated and, thus, monitored by external audits. Others followEurachem/Citac guidelines (e.g., “Quality Assurance for Researchand Development and Non-Routine Analysis”). These documentsare available on an internal, server-based quality information system,which includes listings of relevant Web sites, says Krapp. In addition,staff participate in various training programs, including a specialcourse on quality assurance. The efforts are monitored by interlabo-ratory tests, internal audits, and quality management reviews. Docu-mentation follows the Eurachem/Citac guidelines, which providestraceability and trackability.Krapp has introduced other quality management methods at the

institution, including blank studies, control charts, intermethod com-parisons, and determinations of measurement uncertainties. Thesetypes of quality assurance tools are typically unknown in researchgroups and especially in academia, he says.The effort could spread. Bernd Neidhart, also of GKSS, wants to

establish such techniques widely in universities. Neidhart now chairsthe Eurachem Working Group MAFIA, which translates to manag-ing analytics for implementation in academia.

GOVERNMENT AND SOCIETY


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accreditation with worldwide recognition for testing andcalibration laboratories (Anal. Chem. 1997, 69, 161 A;1999, 71, 314 A). NACLA is not intended to be anotheraccrediting body, but rather a coordinator of accreditingbodies. Eventually, the organization hopes to expand to in-clude accrediting bodies from Mexico and Canada, as wellas the United States (NA would stand for North Americainstead of National). The goal is to establish proceduresand criteria for laboratory accreditation and rules for recip-rocal recognition. Ideally, the system would be acceptedby all U.S. foreign trading partners.Although NACLA appears to be

gaining momentum, several issuesneed to be hammered out beforeimplementation can become a reali-ty. High on the list is for Canadaand Mexico to accept the NACLAprocedures. Representatives fromthe Standards Council of Canada,the Canadian Standards Associa-tion, and EMA (an organizationthat integrates all laboratory acc-reditation in Mexico) have been observing NACLA’sprogress from the sidelines but have not officially joined.Differences between NACLA’s guidelines and bylaws andthose of the other organizations need to be reconciledbefore a merge can take place.As NACLA moves forward, it could also be merged with

other organizations that have similar goals, such as the NorthAmerican Calibration Cooperation (NACC) and the Inter-American Accreditation Cooperation (IAAC), to form aNorth American contingent of the International Laborato-ry Accreditation Cooperation (ILAC). Whereas NACLA isfocused on North America, ILAC is an international forumdedicated to the development of accreditation practices andprocedures around the globe. Having a North Americanvoice in ILAC and the world laboratory accreditation com-munity would facilitate trade between Mexico, Canada, andthe United States and provide North American laboratorieswith an opportunity to reduce the number of accredita-

tions, says Don Wilson of the Standards Council of Canada.On the down side, he says, there are several accreditationbodies already committed to and recognized by the AsiaPacific Laboratory Accreditation Cooperation (APLAC).Because of limited resources, accrediting bodies might notbe able to join all regions.NACLA’s International Affairs Committee, chaired by

Wilson, is working on a draft document, which would allowCanadian, Mexican, and U.S. programs under NACC tomerge into the North American region of ILAC. IAACmay also be part of the arrangement.

Another issue affecting many acc-reditation programs worldwide isincorporation of the new interna-tional standard, ISO/IEC 17025,which replaced Guide 25 in Decem-ber 1999. A workshop was held inApril after the annual meeting tobring NACLA participants up tospeed on the changes involved.According to John Donaldson, vicepresident of the American National

Standards Institute, ILAC is recommending a two-yeartransition period for laboratories to comply with the new17025 requirements.Proficiency testing (PT) is one area that is not as clear-

ly spelled out in 17025 as it is in Guide 25, says MartinHarper of the University of Alabama–Birmingham. NACLAorganizers are currently working to develop an effectivePT program, and they may now even have a bit more flex-ibility because of the new guidelines.Assessor training is also high on NACLA’s priority list.

A training course for evaluators was held in March 1999,and another is planned for early 2001. NACLA is tryingto expand the pool of available evaluators; currently thereare only 14.NACLA is still soliciting members and volunteers to serve

on committees. More information about the organizationcan be found on its Web site (http://ts.nist.gov/nacla).Britt Erickson

Problematic standards

Work carried out by the privately owned

LGC, formerly the U.K.’s Laboratory of

the Government Chemist, has highlight-

ed a serious problem in developing stan-

dard reference materials for environ-

mental monitoring of radioactivity,

according to a report published at the

end of March by the U.K.’s Department

of the Environment (DOE).

Several years ago, the DOE commis-

sioned LGC to develop new natural-

matrix reference materials (NMRMs),

but unforeseen problems arose during

the collection, processing, and valida-

tion of the materials, and the govern-


n ews

ment deadline was not met. Four

NMRMs that were identified as poten-

tially useful were not finalized in the

allocated period of time, although the

LGC says the U.K.’s National Physical

Laboratory (NPL) may ultimately take up

the reins in developing these further.

The need for NMRMs was highlight-

ed as long ago as 1977 at a meeting of

the International Committee on Radionu-

clide Metrology. V. T. Bowen of Woods

Hole Oceanographic Institute pointed

out that natural-matrix materials spiked

with radionuclides were inadequate for

various reasons and the environmental

radiochemistry community must urgently

develop homogeneous natural-matrix

samples, each naturally contaminated

by a range of radionuclides at various

concentration levels.

Radio-NMRMs have been developed

or are under current development by the

likes of the National Institute of Stan-

dards and Technology, the NPL, and the

LGC using materials such as river and

lake sediments, soils, human tissues,

and bone ash.

According to the NPL, a “robust

framework of radioactivity metrology

is essential to support the ongoing

exploitation of nuclear processes and

products.” This makes accurate and

traceable measurements based on stan-

dard references critical to research and

environmental monitoring, which must

stand up to serious public scrutiny. In

recent years, comparisons of environ-

mental radioactivity measurements have

sadly shown discrepancies due to inad-

equate radiochemical techniques and

uncertified methodology.

The LGC carried out a survey of cur-

rently used NMRMs in western Europe

and correlated this with the U.K.’s envi-

ronmental monitoring needs.

Having identified four suitable

matrixes, it was then impossi-

ble to find enough independ-

ent laboratories to take part

in the study, so time ran out

on the contract.

The DOE points out in its

report that the time required

and the costs involved in

undertaking such work should not be

underestimated. Certified NMRMs, it

says, are a “vital part of traceability in

analytical science.” Without these stan-

dards, there is no absolute method of

checking the validity of any measure-

ments recorded in the field.

The DOE is now considering how to

move forward with the four LGC materi-

als. Experts say that there is obviously a

need for reproducibility and the mutual

acceptance of test data without which

the usefulness of measurements are

severely restricted. However, the four

materials from LGC are not, at this time,

at a satisfactory stage of development to

fulfill this role. David Bradley

Growing by columns

Agilent Technologies solidified itsposition in the separations marketwith the acquisition of J&W Scientif-ic—the largest manufacturer and sup-plier of capillary GC columns—onMarch 29. According to the company,the takeover makes Agilent the largestsupplier of GC instruments, consum-ables, and columns. J&W also manu-factures CE and solid-phase extractionproducts.

BUSINESS


news

2000 EAS award winners

The 2000 winners of the Eastern Ana-lytical Symposium (EAS) awards areIsiah M. Warner of Louisiana StateUniversity, Tony Davies of NorwichNear-Infrared Consultancy, Peter Carrof the University of Minnesota, HansW. Spiess of Max-Planck-Institüt fürPolymerforschung, and Svante Wold ofUmëa University. Other awardeesinclude Andy Ewing of PennsylvaniaState University, James Robinson ofLouisiana State University, Maria Kuh-nert-Brandstatter of the University ofInnsbruck, and Kimberly Prather ofthe University of California–Riverside.The awards will be presented at EAS’00 in the fall in Atlantic City, NJ.

Carr, professorat the Universityof Minnesota, willreceive the Awardfor Achievements inSeparation Science,sponsored by Waters.His other interests

include electrochemistry, ion-selectiveelectrodes, thermochemistry, and solute–solvent interactions in chromatography.

Davies, a con-sultant at the Nor-wich Near-InfraredConsultancy (U.K.),will receive theaward for Achieve-ments in Near-IRSpectroscopy, spon-

sored by FOSS NIRSystems. His workhas included NIR spectroscopy andanalysis in the food industry.

Spiess, professorat the Max-Planck-Institüt für Poly-merforschung (Ger-many), will receivethe Award for Ach-ievements in Mag-netic Resonance.

Warner, profes-sor at LouisianaState University, willreceive the Awardfor OutstandingAchievements in theFields of AnalyticalChemistry. Warner’s

research focuses on the development ofimproved methodology for complexchemical studies, such as fluorescencespectroscopy, guest/host interactions,and chemometrics.

Wold, professorat Umëa University(Sweden), will re-ceive the Award forAchievements inChemometrics. Hisresearch interestsinclude multivariate

modeling, and the structure propertyand activity of chemical processes.

Ewing, professorat PennsylvaniaState University, willreceive the Benedet-ti-Pichler Award.Ewing’s researchhas focused on thesmall-volume analy-

sis and measurement of single cells. Hiswork also includes electrochemical de-tection for CE, ultra-small carbon ringelectrodes, and electrochemical meas-urement of exocytosis.

Robinson, pro-fessor at LouisianaState University,will receive the NewYork Section of theSociety for AppliedSpectroscopy GoldMedal Award.

Robinson’s interests include spectro-scopic methods for chemical analysis,atomic absorption spectroscopy, envi-

ronmental analysis, and studies in thecomposition of heart plaque.

Kuhnert-Brandstatter, pro-fessor at the Uni-versity of Innsbruck(Austria), willreceive the NewYork MicroscopicalSociety Earnst

Abbe Award. Her work featuresadvances in the field of thermomicro-scopic analysis, UV and IR spectro-scopies, and polymorphism of drugsubstances.

Prather, profes-sor at the Universityof Califor-nia–Riverside, willreceive the DACFindeis YoungInvestigator Award.Prather’s research

focuses on aerosol time-of-flight MS.

PEOPLE

SACP’s Undergrad-uate AnalyticalProgram Grant

Lori Ellen Stephens, professor at

Rowan University, is the recipient

of the SACP’s 1st Annual Under-

graduate Analytical Program

Grant. The award was established

to promote high-quality, innovative

undergraduate research in analyti-

cal chemistry and train and develop

undergraduate students.

Documents

News from the ACS National Meeting: Why genomics is not enough