Agilent Pesticides App Compend

Agilent Pesticides Applications Compendium

Solutions that meet your demands for

faster and more confident analysis

Table of Contents

GC/MS and LC/MS Analyzers and Application Kits

GC/MS and GC/MS/MS Application Notes

LC/MS and LC/MS/MS Application Notes

Productivity Tools

Sample Preparation Application Notes

Index

The table of contents on the right has been linked to the individual sections in this compendium.

Click on the text to jump to a specific section. If you prefer to search for words or phrases used in any of the enclosed Applications Notes, click on the search button below to open Acrobats search window.

Emerging technologies can help your lab adjust to changing industry requirements. However, implementing these advancements can be hampered by a shortage of time and resources.

That is why, for over four decades, Agilent has taken an active role in developing instruments, methods, and applications that continually set new global standards for applications such as pesticides analysis.

Agilent continually partners with the best, most experienced global food and environmental organizations, laboratories, government agencies, and universities to solve problems and bring new applications to light.

This compendium is a collection of Agilent Application Notes and resources for pesticides analysis. You can browse the applications by technique using the links below.

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GC/MS and LC/MS Analyzers and Application Kits

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A quick, cost-effective paththrough your toughest problemsWith any new technology, getting started is the biggestchallenge. But Analyzers and Application Kits help you spend less time on developing your methods of analysis, and more time generating the highest quality results from new technologies.Ready-to-use packaged workflow solutions:

Factory-tested Analyzers Agilents pre-configured, GC/MS Analyzers, factory tested for pesticide analysis, make it easy to implement the latest technologies that would otherwise require hours or days to apply. So you can start producing consistent, high-quality data from day one.

Application Kits These easy-to-use application packages for Agilent LC/MS instruments include all the tools and components you need to get started quickly with your application.

Analyzing pesticide residues in food and environmental samples is challenging. Large numbers of compounds, many at low concentrations, must be monitored and quantitated. To complicate matters, method development is labor-intensive and time-consuming, due to compound-dependent parameters that must be optimized.

A faster, easier way to develop customized screening methods

Agilents Pesticide Screening Dynamic MRM Application Kit is truly unique, because much of the development work has already been completed. The kit features easy-to-use examples that show you how to set up screening methods and quickly adapt them to your specific needs. It also includes:

A more than 750-Pesticides Dynamic MRM database that includes compound names, MRM transitions, fragmentor voltages, collision energies, and retention times for each database compound for reliable pesticide screening.

Pretested analysis methods, using the Dynamic MRM database, are provided for target screening of pesticides that are routinely monitored around the world.

Minimize the need for tedious manual method development with pretested methods and a Dynamic MRM database The following components are included

saving you time and money:

Pesticide Dynamic MRM database

Positive and negative ion pesticide test mixes

Agilent ZORBAX Eclipse Plus C18 column (2.1 mm 50 mm x 1.8 m)

Free-trial QuEChERS sample preparation kit

Quick-start guide and Application Note that show you how to run the test mixes and create dynamic MRM methods

CD-ROM with examples of screening methods, data files, and reports

Agilent Analyzers and Application Kits

Triple Quadrupole LC/MS Pesticide Application KitQuickly and efficiently implement target screening methods

This information is subject to change without notice. Agilent Technologies, Inc. 2010Printed in U.S.A., July 7, 20105990-5309EN

Faster identification and quantification of pesticides monitored worldwide: Here, a 300-compound pesticide mixture was analyzed using the Agilent 1200 SL Series RRLC and 6460 Triple Quad with Jet Stream Technology.

With over 750 entries, Agilents Pesticide Dynamic MRM database ensures fast, customized method development.

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1.90.6 0.9 3.8 7.2 17.02.2 3.2 6.84.1 18.71.4 4.7 18.2 19.72.7

1 4433221

Put your lab on the productivity fast track.Contact your local Agilent Representative or Agilent Authorized Distributor

Call 800-227-9770 (in the U.S. or Canada)or visit www.agilent.com/chem/appkits

Ordering information: Agilents LC/MS Pesticide Application Kit (G1733AA)

The following are required but not included with the G1733AA kit:

Agilent 1200 Series Rapid Resolution LC System or Agilent 1290 Infinity LC

Agilent 6400 Series Triple Quadrupole LC/MS system

Agilent MassHunter Acquisition Software 3.01 or higher

A more than 750-compound Pesticide Dynamic MRM database and Agilent MassHunter Data Acquisition and Analysis software let you quickly generate acquisition and analysis methods, which can be easily modified to meet your future needs.

The Agilent 1200 Series SL Rapid Resolution LC, interfaced with Agilents 6400 Series Triple Quadrupole LC/MS System delivers fast, high-resolution LC/MS/MS analysis.

Agilents Jet Stream Electrospray lowers detection levels of pesticides in complex matrices.

Dynamic MRM maximizes the Quadrupoles compound capacity without sacrificing sensitivity when hundreds of residues are being analyzed at femtomole concentrations.

Agilent SampliQ QuEChERS sample preparation kits make it quick and easy to extract pesticide residues from complex food matrices.

Quickly establish screening methods for complex matrices using these leading-edge technologies

Pre-developed examples help you start screening for pesticides in a fraction of time

READY TO GO FOR PESTICIDES AND ENVIRONMENTAL POLLUTANTSTriple Quadrupole GC/MS Multiresidue Analyzer

Agilent Analyzers and Applications Kits

Based on Agilents 7890A GC and 7000 Series Triple Quadrupole GC/MS, our Multiresidue Analyzers feature a comprehensive MRM database with more than 1000 pesticides and environmental pollutants. The database is optimized with an average of 8 MRM transitions, plus relative intensities for each compound, helping you minimize matrix interference. It also includes a user-friendly tool that lets you use your own compound list to customize the analyzer acquisition method for your speci c needs in just 5 minutes.

Fully con gured and factory chemically-tested analyzers make it easy to achieve the highest performance for multiresidue analyses incomplex matrices

The following components are included saving you time and maximizing performance: NEW 1000+ compound MRM database, with 8000+

optimized transitions DVD that shows you how to build an optimized MRM

acquisition method based on your compound list Retention Time Locked HP-5MS Ultra Inert column for

reliable peak identi cation and quantitation Checkout samples of 17 representative analytes Capillary Flow Technology and back ush for reduced

maintenance Quick-start guide that allows you to quickly utilize

Agilent advanced technologies and get high performance analytical results on day one

CD-ROM with system-speci c checkout data les and reports

Flexible, comprehensive MRM Database contains over 1000 pesticides and pollutants, and is optimized with an average of 8 MRM transitions to minimize matrix interference. It also includes a tool that makes it easy to build methods based on your own list.

Integrated Capillary Flow Technology (CFT) back ush promotes shorter analysis times, lower chemical background, longer column life, and less frequent ion source cleaning to improve uptime.

Multimode inlet (MMI) with large-volume injection enhances trace-level detection and adds exibility by including hot or cold split/splitless capabilities.

Superior GC/MS/MS selectivity and sensitivity eliminates false results, and simpli es data review for improved productivity.

Productivity tools to help you make the most out of every analysis: Agilent autotune, batch-at-a-glance data review, and parameter-less integrator streamline your data review and processing.

Perform highly sensitive, multiresidue target analysis in complex matrices using these built-in features:

Boost your multiresidue screening productivity with the Agilent GC/MS/MS pesticide and environmental pollutant analyzer

This information is subject to change without notice. Agilent Technologies, Inc. 2011Printed in U.S.A., December 9, 20115990-6045EN

Ordering information: Choose one of the following options when you order an Agilent 7000 Series Triple Quadrupole GC/MS with an Agilent 7890A GC analyzer system: The exibility-driven setup. G3445A Option 411:

GC/MS/MS Pesticide and Environmental Pollutant Analyzer with constant pressure, post-column back ush method

The performance-driven setup. G3445A Option 412: GC/MS/MS Pesticide and Environmental Pollutant Analyzer with constant ow, mid-column back ush method

For customers who already own an Agilent GC/QQQ system: G9250AA: Pesticides and Environmental Pollutants MRM

database

Agilent also offers Single Quadrupole GC/MSD pesticide analyzers for broad screening at 5 to 100 ppb. Each is equipped with CFT Back ush, Deconvolution Reporting Software, and RTL Pesticide and Endocrine Disruptor library. Go to agilent.com/chem/library, brochure 5990-5310EN, for details.

Put your lab on the productivity fast track.Contact your local Agilent Representative or Agilent Authorized DistributorCall 800-227-9770 (in the U.S. or Canada) or visit www.agilent.com/chem/appkits

The G9250AA database has on average 8 transitions for each compound. This allows the user to choose alternative transitions to minimize matrix interferences and improve quantitation results.Coun

ts

Aquisition Time (min)

Ratio=23.3x104

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Orange

95.0 64.0

141.0 80.0

Orange

141.0 95.0

95.0 79.0

Pear

Pear

medium matrix interference(overlapping peak gives

incorrect ion ratio)

Top two transitions of Methamidophos

Two alternative transitions of Methamidophos

minimum matrix interference

strong matrix interference (overlapping peak gives

inaccurate quantitation result)

minimum matrix interference

Based on Agilents 5975C Series GC/MSD and 7890A GCSystem, our user-friendly GC/MSD Pesticide Analyzer quickly screens and quantitates large numbers of pesticidesand endocrine disruptors in a single analysis. Its screeningmethods conform to the latest worldwide pesticide testingrequirements. With inlet, column, capillary flow device, and software tools all installed and configured in the factory,and the Analyzer pre-tested for pesticide analysis you cansave weeks of method development.

Screen more pesticides... in less time

Agilents GC/MSD Pesticide Analyzer makes use of productivity-boosting GC/MS technologies that allow you to:

Increase the number of targets screened

Reduce the analysis time required per sample

Perform a complete screening and quantitation in 2-3 minutes

Produce consistent, high-quality results from day one

Eliminate the need for tedious manual method development with a fully configured and factory-tested Analyzer.

The following components are included with Agilents Pesticide Analyzer saving you time and money.

Pesticide checkout samples

Retention Time locked HP-5MS column ensuringreliable database matching


Video training tutorials for easy learning of moreadvanced Analyzer features

Quick-start guide and Application Note that show you how to run the screening method provided withthe Analyzer

CD-ROM with analysis methods, data files, and report


GC/MSD Pesticide AnalyzerSimplify and accelerate your pesticide screening

Multimode Inlet (MMI) with large-volume injection enhances trace-leveldetection and adds flexibility by includingstandard split/splitless capabilities.

Retention Time Locking (RTL) for consistentretention times after column maintenance andeasy matching with the 927-compoundPesticides and Endocrine Disruptors database.

Deconvolution Reporting Software (DRS) for fast data review in 2-3 minutes persample, with screening and quantitation in one run.

Capillary Flow Technology (CFT) and backflush promote shorter run times, low chemical background, longer column life, and less frequent source cleaning to improve uptime.

Agilent SampliQ QuEChERS samplepreparation kits let you quickly and easilyextract pesticide residues from complex food matrices.

These built-in features make itfaster and easier to screen largenumbers of target compounds incomplex matrices

The Pesticide Analyzer will start your lab on the fast track to betterbroad-range screening

This information is subject to change without notice. Agilent Technologies, Inc. 2010Printed in U.S.A., January 31, 20105990-5310EN

A DRS Checkout Report: You can analyze your results quickly using DeconvolutionReporting Software (DRS) and the RTL Pesticides database.

Running the pesticides checkout sample: A quick-start guide included withAgilents GC/MSD Pesticide Analyzer shows you how to load the pesticidemethod, relock the method to get consistent retention times, and run thecheckout sample.

Matrix

Interference

Target

Deconvolution peaks and spectra

11.82 11.84 11.86 11.88

Ordering information: Order an Agilent 5975C SeriesGC/MSD along with an Agilent 7890A GC system with one of the following options:

SP1 7890-0456: Pesticide DRS Screening GC/MSD Analyzer

SP1 7890-0457: Japanese Positive List DRS Screening GC/MSD AnalyzerPut your lab on the productivity fast track.

Contact your local Agilent Representative or Agilent Authorized Distributor


Conventional multi-target pesticide screening methods arebased upon triple quadrupole technology. However, thesemethods are limited to target compounds, and do not allow a retrospective analysis of collected data.

Packaging sensitive, high-performance (Q)TOF instrumentswith Screening Application Kits overcomes this limitation.Each user-friendly Application Kit combines pretestedanalysis methods with powerful software tools that, together,simplify the setup of screening applications. This enableseven high-volume labs to perform truly comprehensivescreening for large numbers of both target and non-targetcompounds.

Capture all the data, all the time

Using (Q)TOF technology for your pesticides screening allowsyou to retain all spectral data, not just your original range ofinterest. That means you can refer back to your dataanytime without reruns to investigate samples further.

Screen samples quickly and easily usingpretested methods and a Pesticides AccurateMass database The following components are included

saving you time and money:

Agilents 1600-pesticide Personal CompoundDatabase and Library software (PCDL)

Positive and negative ion pesticide test mixes

Agilent ZORBAX Eclipse Plus C18 column (2.1 mm 50 mm x 1.8 m)


Quick-start guide and Application Note thatshow you how to run the test mixes and createscreening methods

CD-ROM with examples of easy-to-usescreening methods, data files, and reports thatdemonstrate method setup and adaptation


TOF and QTOF LC/MS Pesticide Application KitSimplify your broad-range screening for non-target compounds

This information is subject to change without notice. Agilent Technologies, Inc. 2010Printed in U.S.A., April 12, 20105990-5642EN

Here you see an extracted chromatogram of 200 pesticides using the Agilent1200 Series SL LC with the Agilent 6230 TOF.

Agilents Personal Compound database ensures fast, customized methoddevelopment. The screen above gives an example of batch summary results with retention times updated.

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Cpd 323: Tribufos: +ESI ECC Scan Frag=150.0V SeqR_16-r003.d

15.212Cpd 323: Tribufos

Counts vs. Acquisition Time (min)1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Put your lab on the productivity fast track.Contact your local Agilent Representative or Agilent Authorized Distributor


Pre-developed examples help youstart screening for pesticides in afraction of the time

A 1600-pesticide Personal Compounddatabase and Agilent MassHunter DataAcquisition and Analysis software let youquickly generate screening methods, whichcan be modified to meet your future needs.

Industry-leading Rapid Resolution LiquidChromatography (RRLC) and Ultra HighPerformance Liquid Chromatography(UHPLC) separations that enhance yourresults and productivity.

Agilents Jet Stream Electrospray IonSource lowers detection levels of pesticidesin complex matrices.

Best-in-class MS and MS/MS massaccuracy: our (Q)TOF Full Scan capability letsyou access all the data, all the time, openingup endless possibilities for screening multipleanalytes and non-target compounds.

Leading-edge technologies deliverspeed, sensitivity, and powerful datamining tools that make broad screeningaccessible to your lab

Ordering information: Agilents (Q)TOF LC/MSPesticide Application Kit (G6854AA)

The following are required but not included with theG6854AA kit:

Agilent 1200 Series Rapid Resolution LC System or Agilent 1290 Infinity LC

Agilent 6200 Series TOF or 6500 Series QTOF LC/MS system

Agilent MassHunter Qualitative Analysis Software 3.01 or higher

Agilent SampliQ QuEChERS samplepreparation kits make it quick and easy to extract pesticide residues from complexfood matrices.

To demonstrate its functionality, Agilents (Q)TOF PesticideApplication Kit includes a pesticide test mix for both positiveand negative ion modes. A general pesticide screening methodexample is also provided, along with a representative spinachextraction using the Agilent SampliQ extraction and dispersiveSPE kits for complete food analysis.

A quick, cost-effective path through your toughest problemsWith any new technology, getting started is the biggestchallenge. But Analyzers and Application Kits help you spendless time on set-up and configuration, and more timegenerating the highest quality results from new technologies.

Our Analyzer and Application Kit portfolio incorporates thelatest GC, LC, GC/MS, and LC/MS productivity techniques forpesticide screening, forensic toxicology, semi-volatilesanalysis, biodiesel, refinery gas analysis, and many morevalve-based analyzers. And we are continually expanding ourline of kits for critical applications.

Agilent Analyzers and Application Kits:

Thefast trackto greater productivity

Instruments alone do not solve business problems. Knowledgedoes. That is why, for over four decades, Agilent has taken anactive role in developing methods and applications many ofwhich have evolved into global standards for industries such as hydrocarbon processing, environmental, food safety, andforensics/toxicology.

Now, Agilent brings this knowledge directly to your lab with our NEW industry-specific Analyzers and Application Kits.

Actual kit contents may vary based on application.

2Implement advanced technologies quickly and confidentlyNew technologies can help your lab adjust to changingbusiness metrics and industry requirements. However,implementing these technologies to their fullest potential can be hampered by a shortage of time and resources.

An Agilent Analyzer solves this problem by ensuring that your application is appropriately configured for optimalperformance. So you can apply new capabilities with minimaldisruption, shorten your time-to-results (or time-to-market), and realize the full benefit of the latest technologies.

Moreover, Analyzers and Application Kits include currentadvances for increasing analysis speed, improving sensitivity in complex matrices, simplifying data review, and promotingease of use.

Lower your method development costs by up to 90%Developing new methods is time-consuming and costly. Yourmost experienced chemists are busy learning and investigatingnew productivity-enhancing technologies and you cannot yetrun real samples on your new instrument.

That is why Agilent Analyzers and Application Kits include a method of analysis and checkout standard, which decreasethe time and hassle of developing new methods and costly test mixtures.

A unique combination of application-specific tools and ourexpertise can reduce the number ofsteps between start-up and results.

Every Agilent Analyzer and Application Kit is backed by decades of experience, customer feedback, and collaborationswith key laboratories around the world. Analyzers andApplication Kits include:

Applications methodology, column, supplies, and a checkoutstandards mixture so you wont waste time or moneypurchasing individual components

Analyzers also include:

Shipped fully assembled for your application from ourfactory including any hardware or software componentsrequired to optimize the application, minimizing the downtimeand disruption of on-site installation

Factory configured and tested a checkout report atshipping, and a duplicate on-site checkout, make sure thatyour application is ready to go

Concise, application-focused video training tools facilitatesmooth operation right out of the box

And unlike other providers, Agilent Analyzers and ApplicationKits can be custom-tailored to suit your unique needs, ensuringexcellent results throughout the 10-year life of your instrument.

Simplify your startup and reduce the time to technical mastery

Example: Pesticides GC/MS Analyzer

Factory All checkout on the instrument as ordered by the customer Instrument setup and leak tested Application appropriate column, liner and septa installed Retention time locked based on customer instrument Capillary flow device setup based on application DRS, AMDIS database setup according to application Factory run checkout method using application standard mix Signal/Noise check

Delivery Quick start guide to run the checkout method All method and data files on DVD for easy

out of the box operation

Advanced features video tools Consumables included, no separate ordering required Trial SPE QuEChERS kit Easy consumables re-ordering information

Installation Focus is on the startup of the application

Duplicate factory checkout with standard mix on site

Review video tutorials on how to use advanced features

3You choose the level of service that best fits your labEach Analyzer and Application Kit encompasses the latestproductivity-enhancing techniques, such as GC Capillary FlowTechnology, Deconvolution Reporting Software for fast datareview and reporting, or LC/MS and GC/MS mass databases for efficient screening of large compound groups. Individualcomponents and services may include:

Method of analysis, column, supplies, and checkout samples

DVD with method parameters

Video training tools*

Factory checkout*

Sample preparation pack*

Application Notes

Quick-start guide

Optimization of the analysis

Testing and verification with an appropriate suitability standard*For select systems.

Start your lab on the fast track to success.Contact your local Agilent Representative or Agilent Authorized Distributor at www.agilent.com/chem/contactus

Or call 800-227-9770 (in the U.S. or Canada)

Visit www.agilent.com/chem/appkits for a description of available kits and their contents.

Employ the very latest technologies without worrying about your first resultsConcern about questionable results can be a significantobstacle to investigating newer, more productive methods and technologies. But an Agilent Analyzer or Application Kit can help you produce consistent, high-quality data right from day one.

The products, supplies, and optimization services in AgilentAnalyzers and Application Kits can help you achieve the lowestpossible detection limits while reducing or eliminating falsepositives and negatives. In addition, our LC/MS kits areequipped with databases that can increase your ability toautomatically find compounds in matrices such as fruits,vegetables, and body fluids.

Together with a comprehensive database, a preconfigured,pretested system can help you achieve reliable sample screeningand confirmation, while helping you take full advantage of theproductivity gains that new technologies offer.

Capillary FlowTechnology

(CFT)

RTL databases for 927

pesticidecompounds

Deconvolution Reporting SW

(DRS)

SynchronousSIM/SCAN

App. specificsupplies

Sample PrepQuEChERS

RRLC/UHPLC

App. specificsupplies

Sample PrepQuEChERS

Jet StreamTechnology

Dynamic MRM

MassHunterSW

PCD or DMRMdatabase

Multimode Inlet

Retention Time Locking (RTL)

As a supplement to our new Analyzers and Application Kits,Agilent also delivers local, on-site assistance at the followinglevels:

Training courses and application consulting that teach you the best practices for running your samples

Extensions to your standard warranty coverage

Preventive maintenance for your complete system

On-site duplicate factory checkout

We also provide customized solutions in conjunction with our Agilent Channel Partners.

Whether you need to improve data integrity, reduce matrixinterference, or decrease your consumption of columns andsupplies, Agilents extensive industry knowledge and technicalexpertise can help you meet your most challenging analyticaldemands and timeframes.

Contact your Agilent Representative today to discuss your specific needs.

Learn more about individual kits and their contents: www.agilent.com/chem/appkits

Find an Agilent customer center in your country: www.agilent.com/chem/contactus

U.S. and Canada 1-800-227-9770 [email protected]

Europe [email protected]

Asia Pacific [email protected]

This information is subject to change without notice. Agilent Technologies, Inc. 2009Printed in U.S.A., August 28, 20095990-4116EN

Beyond the box:

Advice and support customized for your samples

For more information

GC/MS and GC/MS/MS Application Notes

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The GC/MS/MS Analyzer and thePesticides and Environmental PollutantsMRM Database

Application Note

Abstract

Based on an Agilent 7890A GC System and an Agilent 7000 Series Triple Quadrupole

GC/MS, these GC/MS/MS Multiresidue Analyzers were developed to simplify a labs

startup process. The database has an average of eight MRM transitions with relative

intensities for each compound to provide alternative measurements for minimizing

matrix interferences. Easy-to-use tools, as well as tutorial videos are included in the

database to build an MRM acquisition method based on your list of compound CAS

numbers in less than 5 minutes.

Introduction

Pesticide residue analysis is a complex task requiring the analyst to search fordozens, or even hundreds, of compounds in a wide variety of crop or environmentalmatrices. Triple Quadrupole GC/MS (GC/MS/MS) provides excellent sensitivity andselectivity in analyzing complex matrices. Agilent Technologies offers several pre-configured and pretested GC/MS/MS analyzers to simplify a labs startup process.The analytical capability of a lab, however, is largely determined by the complete-ness of the MS/MS MRM transitions in an acquisition method. AgilentTechnologies developed an MS/MS MRM Pesticides and Environmental PollutantsDatabase (G9250AA) of over 1,070 compounds to address many of the limitationsmost labs are facing. This database is in the form of a spreadsheet for ease-of-use.Significant efforts were invested to acquire multiple transitions (eight on average,with relative intensities) of each compound in the database to work around matrixinterferences.

Food Safety and Environmental

Author

Chin-Kai Meng

Agilent Technologies, Inc.

2850 Centerville Road

Wilmington, DE 19808

USA

2Key features of the MS/MS MRM Database include:

Allows users to build acquisition methods without buyingall compound standards, thus saves time and money

Includes retention times for either constant flow or con-stant pressure methods; corresponding retention index (RI)values are also included for easy migration to other GCoven programs

Has multiple MS/MS transitions, eight on average, foreach compound which provides alternatives to workaround matrix interferences

Shows relative intensity of each MS/MS transition withina compound that facilitates transition selection

Allows a quick sort according to compound category(phthalates, PAHs, organophosphorus, fungicides, or semi-volatile pollutants and so forth, see Appendix A), CASnumber, molecular formula, or molecular weight and soforth.

Using the tools in the database, an MRM acquisition method,based on a list of compound CAS numbers, can be easily cre-ated from a subset of MS/MS transitions in the database inless than 5 minutes.

Experimental Conditions

Sample PreparationWithout proper extraction and cleanup procedures, it is diffi-cult to detect trace levels of analytes in complex matrices.The QuEChERS sample preparation technique was first intro-duced for pesticide analysis in foods by USDA scientists in2003 [1]. It has been rapidly accepted worldwide for multi-residue pesticide analysis due to its special features knownas Quick, Easy, Cheap, Effective, Rugged, and Safe. TheQuEChERS extracts can be analyzed by LC and GC combinedwith MS to determine a wide range of pesticide residues.

Agilents QuEChERS extraction kits and dispersive SPEcleanup kits have demonstrated excellent recoveries for thefrequently used pesticides in different food matrices [2, 3].The sample extracts used in this study were prepared usingthe QuEChERS technique as described in an application noteby Zhao, L. et al [4].

GC/MS/MS AnalyzerThe Multiresidue GC/MS/MS Analyzer is configured withAgilents proprietary Capillary Flow Technology (CFT), enablingrugged, reliable GC column backflushing. Backflushing the GCcolumn shortens run times, extends column life, reduceschemical background, provides consistent retention times andspectra, and keeps the MS ion source clean. A Multi-ModeInlet (MMI) provides the flexibility to inject samples in cold,hot, or solvent-vent modes. Each analyzer system is testedwith a 17-compound mixture and retention-time locked at thefactory.

Two hardware configurations are available to meet differentlab needs (see Figure 1):

G3445A option 411: This configuration is based uponconstant pressure mode method with post-column back-flushing. It provides the flexibility to add GC detectors andcan be easily scaled for shorter run times.

G3445A option 412: This configuration is based uponconstant flow mode method with mid-column backflushing.This method provides ultimate performance and shortercycle times with reduced carrier gas consumption.

Both configurations (option 411 and option 412) are inter-changeable by changing the column and adding or removing acapillary flow-restrictor. A Quick Start Guide for each analyzerdiscusses the retention time locking, checkout method resultsand report for your specific system, a list of supplies, andsome troubleshooting tips.

3MethodsThere are three sets of method parameters included with thedatabase. Some of the method highlights are shown inTable 1.

Inlet MS/MS

Purgedultimateunion

Purgedultimateunion

EPCConstant pressurePost-column backflush

Constant flowMid-column backflush

1070+ compoundsMRM Database

1070+ compoundsMRM Database

G3445A option 411 Setup

G3445A option 412 Setup

Flexible to add GC detectors and easily scaled for shorter run times

Inlet MS/MS

EPC

Provides ultimate performance and the shortest cycle time

30 m HP-5ms UI

15 m HP-5ms UI 15 m HP-5ms UI

Figure 1. System configurations of Agilent GC/MS/MS Multiresidue Analyzers.

Method 1 Method 2 Method 3

Run time 40.5 min 41.867 min 19.75 min

Column flow Constant flow mode Constant pressure mode Constant flow mode

Feature Allowing many more transitions in an analysis than Method 3

MS/MS Analyzer G3445A option # 411 MS/MS Analyzer G3445A option # 412

Column(s) Agilent J&W HP-5ms UI 0.25 mm 15 m, 0.25 m (two each)

Agilent J&W HP-5ms UI 0.25 mm 30 m, 0.25 m (one each)

Agilent J&W HP-5ms UI 0.25 mm 15 m, 0.25 m (two each)

Oven program Initial at 60 C, hold for 1 min40 C/min to 120 C, hold for 0 min5 C/min to 310 C, hold for 0 min

Initial at 70 C, hold for 2 min25 C/min to 150 C, hold for 0 min3 C/min to 200 C, hold for 0 min8 C/min to 280 C, hold for 10 min

Initial at 60 C, hold for 1 min40 C/min to 170 C, hold for 0 min10 C/min to 310 C, hold for 2 min

Locking compound and RT Chlorpyrifos-methyl locked to 18.111 min Chlorpyrifos-methyl locked to 16.593 min Chlorpyrifos-methyl locked to 9.143 min

MS source temperature 300 C 300 C 300 C

Quad temperature Q1 = Q2 = 180 C Q1 = Q2 = 180 C Q1 = Q2 = 180 C

Backflush Mid-column, post-run Post-column, post-run Mid-column, post-run

Table 1. Method Parameters Included with the Databases

4Additional method details for each method are listed on indi-vidual pages (tabs) in the database.

The retention times (RTs) and retention indexes (RIs) corre-sponding to these three sets of methods are included for allcompounds in the database. Therefore, you can either useone of the above prescribed methods (use RTs in the data-base) or your existing lab method (convert database RIs toexpected RTs for your method). The database RIs were calcu-lated using retention times of straight-chain hydrocarbonsfrom C-8 to C-35. An RI_to_RT conversion tool is includedwith the database, so you can calculate expected retentiontimes of your analytes based on the RIs in the database andRTs of hydrocarbon markers (C-8 to C-35) from your existingGC method. If your existing method uses HP-5ms UI columnof the same phase ratio as a 0.25 mm, 0.25 m column, youwill see the smallest difference between the expected andactual retention times for your analytes.

BackflushFood or environmental extracts after cleanup are usually stillvery complex containing various matrix residues such as high-boiling compounds. The extracts used in GC/MS analyses cancause contamination and deterioration of the analyticalcolumn and MS ion source, affecting data quality due to poorpeak shape and loss of responses of active analytes. It alsoleads to a shorter lifetime of the analytical columns and fre-quent MS maintenance. Therefore, it is necessary to use besttechniques and supplies to achieve reliable results and to pro-tect the analytical column and MS ion source.

Column backflushing can be beneficial for the analysis ofcomplex extracts because it significantly reduces analysistime and reduces both column head trimming and MSD ionsource cleaning frequency [5]. Agilent CFT makes columnbackflushing routine [6, 7].

Database OverviewThe G9250AA MRM Database is in Microsoft Excel format foreasy searching and filtering. Compounds are separated bycolor bands for clarity. The following basic compound informa-tion is included for each compound:

Common name

Molecular formula

Molecular weight (averaged)

Molecular weight (mono-isotopic)

CAS number, without dashes for easy sorting

Classification 1 (see Appendix A)

Classification 2 (see Appendix A)

Retention times (RT) and retention indexes (RI) for constant flow and constant pressure methods (totalthree methods)

Relative intensity of each transition within a compound

Chinese name and Japanese name where available

In addition, information is included for building MassHunterMRM acquisition methods:

CAS number, standard format with dashes

Method RT

Common name

ISTD (true or false)

Precursor ion

MS1 resolution

Product ion

MS2 resolution

Dwell time

Collision energy (Voltage)

Retention time window (used in the MassHunterCompound List Assistant tool)

Figures 2 and 3 give an overview of the database layout. Usingthe Excel filtering tool, it is easy to display the table arrayaccording to the criteria chosen in any column. Figure 4 showsthe database after using Excel filtering in column AE to hide alltransitions except the top two (Q0 and Q1). This flexibilityallows the user to build methods according to compound cate-gories, (for example, PAHs, Phthalates, or PCBs), or regulatorymethods and so forth. Two groups of compound classificationsin the Database are listed in Appendix A as a reference.

5Figure 2. Layout of the Database 1: molecular weights, classifications, and three RTs and RIs.

Averageand exactMolecularWeight

Each compound isclassified in two ways

Database has RTs (and RIs) to be used with threeGC methods (CF-40 min, CP-40 min, and CF-20 min

(Color Scale): Orange denotes strong intensity and bluedenotes weak intensity among ALL transitions.

MassHunter format forbuilding acquisition methods

One Quant (Q0) and severalQualification ions for each compound

The scale and relativeintensities of transitions

Figure 3. Layout of the Database 2: MassHunter format for building acquisition methods, multiple transitions, and relative intensities.

6Table 2 gives a breakdown of the compounds included in thedatabase.

Use the filtering function to quicklyselect a Quant (Q0) and a Qualifierion to build an acquisition method

Figure 4. Using Excel filter to hide all transitions except the top two of each compound.

Total number

Pesticides (fungicides, herbicides, insecticides, rodenticides, and others)

675

Breakdown products 42

Deuterated compounds 6

Polybrominated Diphenyl Ether (PBDE) 4

Polybrominated Biphenyl (PBB) 1

Polychlorinated Biphenyl (PCB) 209

Polycyclic Aromatic Hydrocarbon (PAH) 26

Phthalates 17

Additional semivolatile pollutants 94

A complete list of compounds can be found on the DBCompound List tab in the database.

There are three videos included with the database to help theuser learn the database:

An overview of the content and layout of the database. & Each individual column and tab is explained in the

video.

A tutorial of building an MRM acquisition method basedon your list of compound CAS numbers.

& An MRM acquisition method, based on your list of CASnumbers, can be easily and quickly created from a subset of MS/MS transitions in the database.

A tutorial showing how to add new compounds to thedatabase.

The database ReadMe file shows a few Excel shortcuts to usewith the database and a few additional ways of using thedatabase. For example, it shows how to find all nitrogen con-taining compounds in the database, or how to select all PCBcongeners, or the 14 most toxic PCB planar congeners in the database.

Table 2. Compounds Included in the Database

7Results and Discussion

Chemical Background from the MatrixFigure 5 shows four MRM total ion chromatograms (TICs) ofpepper, spinach, orange, and pear extracts acquired usingmethod 3 described on page 3. Thirty-five analytes at 10 ppbeach were spiked in each matrix. Seven transitions of eachanalyte were used in the acquisition method. The TICsshowed that the chemical background from the four matriceswas quite different and sizeable. In this study, pear extractshowed the highest background response in terms of numberof peaks and intensity. The TIC from the orange extract wasthe cleanest among the four chromatograms. These differentand high background responses all came from the matrix. Tounderstand the matrix effect, we need to evaluate the chemi-cal background in each individual transition.

105

0

1

2

3

5 6 7 8 9 10 11 12 13 14 15 16 17 18

Pepper

Spinach

Orange

Pear

105

0

1

2

3

105

0

1

2

3

105

0

1

2

3

Figure 5. Total ion chromatograms (TICs) of pepper, spinach, orange, and pear extracts including 35 analytes spiked at 10 ppb each.

8Small matrix interference

Spinach

Strong matrix interference(overlapping peak givesinaccurate quantitation result)

Pear Orange

Medium matrix interference(overlapping peak gives incorrection ratio)

141 & 95

95 & 79

Minimum matrix interference Minimum matrix interference

141 & 80

95 & 64

Pear Orange

Figure 6. Top two transitions of methamidophos (at 10 pg) in three matrices.

Figure 7. Two alternative methamidophos transitions with minimum matrix interference.

A typical MRM database or acquisition method has two MRMtransitions for each analyte. Figure 6 shows extracted ionchromatograms (EICs) of the top two transitions of methami-dophos (at 10 pg) in three matrices. The retention time ofmethamidophos is about 4.6 minutes. The transitions arearranged in the descending order of responses with the largerone on top. Figure 6 shows the obvious issues of getting inac-curate quantitation results due to medium or strong matrixinterference. For orange matrix, an overlapping peak in thesecond transition marked by a blue arrow, affected integrationresults and the qualifier ion ratio. For pear matrix, an overlap-ping peak in the first transition, marked by a green arrow,which is typically used for quantitation, gave higher and inac-curate quantitation results.

If a user only has two MRM transitions available for each ana-lyte, it is difficult to work around the matrix effect as seen inFigure 6. The G9250AA database has an average of eight tran-sitions for each compound. This allows the user to choosealternative transitions easily when matrix interference affectspeak shape and integration results.

Figure 7 shows EICs of two alternative methamidophos transi-tions in the database. Both transitions showed minimummatrix interferences in orange and pear matrices. In fact, theEICs of these two transitions showed minimum matrix inter-ference in all four matrices. Although these two transitions donot provide the highest responses, they are suited for a uni-versal or screening MRM method. It is always best to evalu-ate the chemical background of an analytes multiple transi-tions in different matrices before selecting the most appropriate transitions in a particular matrix.

9Signal-to-Noise RatiosEvaluating the signal-to-noise ratios (S/N) of MRM transi-tions is another way to identify matrix effects. Some pesti-cides showed consistent MRM responses in different matri-ces, but many pesticides had different MRM responses in dif-ferent matrices due to either matrix enhancement or matrix suppression.

Figure 8 shows responses, or area counts, and S/Ns of sev-eral MRM transitions for four analytes in spinach and orangematrices. The orange dashed line and dark green dotted linerepresent area counts from four or five MRM transitions ofeach analyte in these two matrices. The solid blue and greenlines represent the S/N from the same MRM transitions inthese two matrices. The dashed and dotted lines, signifyingarea counts, superposed tightly. However, the solid lines,S/N, showed significant variations for some transitionswithin each analyte. Using atrazine as an example, the areacount for transition 215&58 was about the same (approxi-mately 7,000) for both matrices, but the S/N for this transition

in spinach was about 40% higher than the S/N in orangematrix. In contrast, for transition 200&122, the S/N in orangematrix was almost double the S/N in spinach, even thoughthe area counts in both matrices were about the same(approximately 4,000). This matrix effect was not unique toatrazine. The S/N variations from some of the MRM transi-tions of dichlorvos and lindane were more pronounced eventhough the area counts were comparable in both matrices.Again, if the number of MRM transitions available for eachanalyte is limited to two or three, it is difficult to select opti-mal MRM transitions suited for the matrix analyzed.

The multiple transitions available in the G9250AA databaseallow users to choose several selective transitions to achieveaccurate confirmation and quantitation results. This studyshowed that MRM transitions should be chosen according tomatrix to achieve optimal and reliable quantitation results. Itis important to use matrix-matched calibrations and low back-ground transitions to achieve accurate quantitation results.

0

500

1000

1500

2000

2500

3000

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

109 &

79

185 &

93

187 &

93

145 &

109

136 &

42

136 &

94

142 &

96

125 &

47

215 &

58

200 &

94

173 &

138

215 &

200

200 &

122

181 &

145

219 &

183

217 &

181

183 &

147

Sol

id L

ines

are

Sig

nal/

Noi

se

Das

h Li

nes

are

Abs

olut

e R

espo

nses

(are

a)

Signal-to-Noise Ratio Comparison for MRM Transitions in Spinach and Orange

50 ppb Spinach, resp. 50 ppb Orange, resp. 50 ppb Spinach, S/N 50 ppb Orange, S/N

Dichlorvos Acephate Atrazine Lindane

Responses (area)in spinach andorange

S/N

Figure 8. Comparison of area counts and signal-to-noise ratios of four analytes MRM transitions in spinach and orange matrices.

10

ConclusionBased on the Agilent 7890A GC and 7000 Series TripleQuadrupole GC/MS, the GC/MS/MS Multiresidue Analyzerswere developed to simplify a labs startup process. A specialfeature of the analyzer is the comprehensive and flexibleMRM database of over 1,070 pesticides and environmentalpollutants. The analyzer also includes CFT backflush for superior system robustness during routine operations.

Matrix can cause quantitation interference, lower responses,or poor peak shape. Each matrix has a different matrix effect.Therefore, it is critical to choose the most selective transitionsfor a particular matrix and use matrix-matched calibrationcurves to achieve accurate and reliable quantitation results.The G9250AA MRM Database has an average of eight MRMtransitions with relative intensities for each compound to pro-vide alternative measurements to minimize matrix interfer-ence. Easy-to-use tools as well as tutorial videos are alsoincluded in the database to build an MRM acquisition methodbased on your list of compound CAS numbers in less than5 minutes.

References

1. M. Anastassiades and S.J. Lehotay, Fast and EasyMultiresidue Method Employment AcetonitrileExtraction/Partitioning and Dispersive Solid-PhaseExtraction for the Determination of Pesticide Residues inProduce, J. AOAC Int., 2003, 86, 412- 431.

2. L. Zhao, D. Schultz, and J. Stevens, Analysis of PesticideResidues in Apple Using Agilent SampliQ QuEChERSAOAC Kits by GC/MS, Agilent Technologies publication5990-4068EN.

3. L. Zhao and J. Stevens, Analysis of Pesticide Residues inSpinach Using Agilent SampliQ QuEChERS AOAC Kits byGC/MS, Agilent Technologies publication 5990-4305EN.

4. L. Zhao and C.-K. Meng, Quantitative and RepeatabilityAnalysis of Trace Level Pesticides in Plantation Food byGC/MS/MS, Agilent Technologies publication 5990-9317EN.

5. M.J. Szelewski and B. Quimby, New Tools for RapidPesticide Analysis in High Matrix Samples, AgilentTechnologies publication 5989-1716EN.

6. C-K. Meng, Improving Productivity and Extending ColumnLife with Backflush, Agilent Technologies publication5989-6018EN.

7. P.L. Wylie and C-K. Meng, A Method for the TraceAnalysis of 175 Pesticides Using the Agilent TripleQuadrupole GC/MS/MS, Agilent Technologies publica-tion 5990-3578EN.

For More Information

For more information on our products and services, visit ourWeb site at www.agilent.com/chem.

11

List of secondary compound classification in the Database

List of First Compound Classification in the Database

Appendix A

algicide herbicide safener insecticide, plant growth regulator

bird repellent herbicide, algaecide microbiocide

breakdown herbicide, microbiocide microbiocide, fungicide

defoliant, plant growth regulator herbicide, plant growth regulator molluscicide

deuterated insect attractants nematicide

fragrance insect growth regulator plant growth regulator

fumigant insect repellent, synergist plant growth regulator, herbicide

fungicide insecticide pollutant

fungicide, insecticide insecticide, fungicide rodenticide

fungicide, microbiocide insecticide, insect repellent synergist

fungicide, plant growth regulator insecticide, molluscicide wood preservative, microbiocide

herbicide insecticide, nematicide

1,3-Indandione Dinitrophenol derivative Phthalate

2,6-Dinitroaniline Diphenyl ether Phthalic acid

Amide Dithiocarbamate Picolinic acid

Anilide Folpet Pyrazole

Anilinopyrimidine Formamidine Pyrethroid

Aromatic Formamidine Pyrethroid ester

Aryl phenyl ketone Fumigant Pyridazine

Arylalanine Halogenated organic Pyridazinone

Aryloxyphenoxy propionic acid Hydrobenzonitrile Pyridine

Auxins Hydroxybenzonitrile Pyridinecarboxylic acid

Benzamide Imidazolinone Pyrimidinamine

Benzimidazole Juvenile hormone mimics Pyrimidine

benzofuranyl alkylsulfonate Keto-enol Pyrimidine organothiophosphate

Benzoic acid Mercaptobenzothiazole Pyrimidinyloxybenzoic acid

Benzothiazole Morphactins Pyrrole

Botanical Morpholine Quinoline

Bridged diphenyl Naphthalene acetic acid derivative Quinone

Carbamate Neonicotinoid Quinoxaline

Carbanilate Nitrophenyl ether SemiVOC

Carbofuran N-Methyl carbamate Strobin

Carboxamide Organochlorine Substituted benzene

Chitin synthesis inhibitor Organophosphorus Sulfite ester

Chlorinated phenol Oxadiazolone Thiadiazole

Chloroacetanilide PAH Thiocarbamate

Continued

www.agilent.com/chemAgilent shall not be liable for errors contained herein or for incidental or consequentialdamages in connection with the furnishing, performance, or use of this material.

Information, descriptions, and specifications in this publication are subject to changewithout notice.

Agilent Technologies, Inc., 2011Printed in the USANovember 10, 20115990-9453EN

Chlorophenoxy acid or ester PBB Thiophthalimide

Conazole PBDE Triadimefon

Coumarin PCB Triazine

Cyclic dithiocarbamate Phenol Triazinone

Cyclodiene Phenoxyacetic Triazole

Cytokinins Phenoxybutyric Triazolone

Defoliant Phenoxypropionic Uracil

Deuterated PAH Phenylsulfamide Urea

Deuterated semiVOC Phosphoramidate Xylylalanine

Dicarboximide Phosphorodiamide

List of secondary compound classification in the Database

Organophosphorus Pesticides Analysis Usingan Agilent J&W DB-5ms Ultra Inert CapillaryGC Column

Abstract

Agilent Technologies Inc. has implemented new testing procedures to more effective-

ly evaluate GC column inertness performance. This new testing procedure employs

deliberately aggressive probes to thoroughly investigate and verify column inertness

and quality. In challenging separations, knowing that the GC column has been thor-

oughly investigated for column inertness gives analysts higher confidence in the

accuracy of their results.

Trace- and ultra trace-level pesticide analyses are important tools for accessing food

supply and environmental quality worldwide. In this application note, trace-level

organophosphorus pesticide analysis is demonstrated using electron impact single

quadrupole scanning mass spectrometry. Agilent's J&W DB-5ms Ultra Inert capillary

GC column provides excellent peak shape for even the most problematic pesticides.

Authors

Doris Smith and Kenneth Lynam


2850 Centerville Road


USA

Application NoteEnvironmental

2Introduction

Pesticides are commonly used in agricultural and residentialapplications throughout the world. Organophosphorus pesti-cides make up approximately 70 percent of the insecticidescurrently in use. Unfortunately, these highly toxic materialshave three main routes of human exposure: inhalation, inges-tion, and skin penetration. Sources of these exposuresinclude consumption of foodstuff containing pesticideresidues, aerosol inhalation, and dermal contact during pesticide application. [1]

Organophosphorus pesticides use the same mechanism ofaction as deadly nerve agents such as sarin, soman, and VX.These pesticides affect the nervous system of insects, mam-mals, and wildlife by inhibiting the enzyme cholinesterase,important in helping regulate nerve impulses. Inactivation ofcholinesterase leads to the accumulation of the neurotrans-mitter acetylcholine in the central and peripheral nervous sys-tem, which leads to depressed motor function and respiratorydepression. Human toxicities for this class of molecules haveshown acute as well as chronic effects from pesticide poisoning. [2,3]

Organophosphorus pesticides tend to be difficult to quantifydue to poor peak shape, as evidenced by broad, asymmetricalpeaks. An EPA Method 525.2 standard containing organ-ophosphorus pesticides along with a custom pesticide mixacquired from Ultra Scientific (North Kingstown, RI) were ana-lyzed to highlight the value of using a 30-m Agilent J&W DB-5ms Ultra Inert capillary GC column for difficult pesticideanalysis. Many pesticides are sensitive to chromatographicsystem activity and will readily breakdown. The UltraScientific custom mix contains several types of these pesti-cides, which are useful in quickly evaluating system perfor-mance with particularly challenging pesticide analytes.Capillary GC column activity as a potential source of resultuncertainty has been virtually eliminated with the Ultra Inertseries of columns. [4]

Experimental

An Agilent 6890N GC/5975B MSD equipped with a 7683Bautosampler was used for this series of experiments. Table 1lists the chromatographic conditions used for these analyses.Table 2 lists flow path consumable supplies used in theseexperiments.

Table 1A. Chromatographic Conditions for EPA Method 525.2 Calibration Standards

GC Agilent 6890N/5975B MSD

Sampler Agilent 7683B, 5.0-L syringe (Agilent p/n 5181-1273) 1.0-L splitless injection

Carrier Helium 44 cm/sec, 1.5 mL/min constant flow

Inlet Pulsed splitless; 250 C, 40 psi until 0.75 min, purge flow 50 mL/min at 1.0 min

Inlet liner Deactivated dual taper direct connect (Agilent p/n G1544-80700)

Column Agilent J&W DB-5ms Ultra Inert 30 m 0.25 mm 0.25 m (Agilent p/n 122-5532UI)

Oven 40 C (1 min) to 110 C (50 C/min), 7 C/min to 190 C, 12 C/min to 285 C, hold 2 min.

Detection MSD source at 250 C, quadrupole at 150 C, transfer line at 280 C, EI mode, scan range 45450 amu

Table 1B. Chromatographic Conditions for Ultra Scientific Calibration Standards

GC Agilent 6890N/5975B MSD

Sampler Agilent 7683B, 5.0-L syringe (Agilent p/n 5181-1273) 1.0-L splitless injection

Carrier Helium 52 cm/s, constant flow

Inlet Pulsed splitless; 250 C, 40 psi until 0.75 min, purge flow 50 mL/min at 1.0 min

Inlet liner Deactivated dual taper direct connect (Agilent p/n G1544-80700)

Column Agilent J&W DB-5ms Ultra Inert 30 m 0.25 mm 0.25 m (Agilent p/n 122-5532UI)

Oven 75 C to 175 C (15 C/min), 10 C/min to 275 C (1 min)

Detection MSD source at 250 C, quadrupole at 150 C, transfer line at 280 C, EI mode, scan range 45450 amu

Table 2. Flow Path Supplies

Vials Amber crimp-top glass vials (Agilent p/n 5183-4496)

Vial caps Crimp caps with 11-mm septa (Agilent p/n 5181-1210)

Vial inserts 100-L glass/polymer feet (Agilent p/n 5181-8872)

Syringe 5 L (Agilent p/n 5181-1273)

Septum Advanced Green (Agilent p/n 5183-4759)

Inlet liners Deactivated dual taper direct connect (Agilent p/n G1544-80700)

Ferrules 0.4 mm id short; 85/15 Vespel/graphite (Agilent p/n 5181-3323)

20x magnifier 20x magnifier loupe (Agilent p/n 430-1020)

3Sample Preparation

A six-component EPA Method 525.2 pesticide standard mixand internal/surrogate standard mix were purchased fromAccu-Standard (New Haven, CT) and used to prepare a six-level calibration standard set. The stock pesticide solution asdelivered had a nominal concentration of 1,000 g/mL. Theinternal/surrogate solution as delivered had a nominal con-centration of 500 g/mL. The calibration standards were pre-pared with component concentrations of 10, 5, 2, 1, 0.5, and 0.1 g/mL and a constant level of 5 g/mL of internal/surro-gate standard as per EPA Method 525.2. All solutions wereprepared in acetone using class A volumetric pipettes andflasks. Acetone used was JT Baker Ultra Resi Grade pur-chased thorough VWR International (West Chester, PA).Acetone was used as a reagent blank and syringe wash solvent.

An 11-component pesticide standard mix was purchased fromUltra Scientific and used to prepare a seven-level calibrationstandard set. The stock pesticide solution as delivered had anominal concentration of 1,000 g/mL. The calibration stan-dards were prepared with component concentrations of 10, 5,2.5, 1, 0.5, 0.25, and 0.1 g/mL. All solutions were prepared in2,2,4-trimethylpentane using class A volumetric pipettes andflasks. The 2,2,4-trimethylpentane used was JT Baker UltraResi Grade purchased thorough VWR International (WestChester, PA). 2,2,4-Trimethylpentane was used as a reagentblank and syringe wash solvent.

Results and Discussion

Baseline Inertness Profile for Ultra Inert Columns

The basic approach for inertness verification for the AgilentJ&W Ultra Inert series of capillary GC columns is testing withaggressive active probes at low concentration and low tem-perature. [5] This is a rigorous approach that establishes con-sistent baseline inertness profiles for each column in theAgilent J&W Ultra Inert GC column series. The baseline inert-ness profile then serves as a predictor for successful analysisof chemically active species that tend to adsorb onto active

sites, particularly at trace level, like the organophosphoruspesticides in this application example. A more detaileddescription of the test mix and additional application exam-ples can be found in references 6 through 8.

Organophosphorus Pesticide Analysis

In this application note, a multilevel pesticide calibrationcurve set was evaluated over the concentration range of 0.1 to 10 g/mL on an Agilent J&W Ultra Inert DB-5 ms 30 m 0.25 mm 0.25 m (Agilent p/n 122-5532UI). Separate cali-bration curves were developed for both the EPA 525.2organophosphorus and Ultra Scientific standards. The stan-dard levels used for the 525.2 calibration were 0.1, 0.5, 1, 2, 5,and 10 g/mL, while the Ultra Scientific calibration levelswere 0.1, 0.25, 0.5, 1, 2.5, 5, and 10 g/mL. The custom pesti-cide standard from Ultra Scientific was used to determinesystem performance by analyzing difficult pesticides, such asendrin and p,p'-DDT, which are prone to analyte breakdown.

No tailing was observed for any of the organophosphoruspesticide peaks across the range studied in either standardset. Sharp, symmetrical peak shapes were noted for all theorganophosphorus pesticides analyzed. Good resolution wasobtained for each of the pesticides investigated.

Linearity for the 525.2 standard components was excellentacross the range studied, giving R2 values of 0.997 or greaterin all cases but fenamiphos, which had an R2 value of 0.978.This value increases to 0.991 at the midlevel concentrationsas suggested by EPA Method 525.2 Sec. 13.2.3.3. Figure 5indicates the correlation coefficients for each of the individualpesticides and shows an example linear regression plot fordisulfoton.

Linearity for the Ultra Scientific standard components wasalso quite good across the range studied. R2 values of 0.990or greater were obtained for the organophosphorus pesti-cides. Figure 6 indicates the correlation coefficients for eachof the individual pesticides and shows an example linearregression plot for mevinphos.

41. 1,3-Dimethyl-2-nitrobenzene (SS)2. Acenapthene-d10 (IS)3. Cycloate4. Prometron5. Phenanthrene-d10 (IS)6. Disulfoton

7. Ametryn8. Fenamiphos9. Tribufos (DEF)10. Triphenylphosphate (SS)11. Chrysene-d12 (IS)12. Perylene-d12 (SS)

6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

65000

70000

Time

Abundance

21 3

4

5

6

7

8

9

10 11 12

Figure 1. Total ion chromatogram (scan mode) of the 1-ng on-column EPA Method 525.2 standard solution loading on an Agilent J&W DB-5ms Ultra Inert 30 m 0.25 mm 0.25 m capillary GC column (p/n 122-5532UI). Chromatographic conditions are listed in Table 1A.

13.5013.00 14.00 14.50 15.00 15.50 16.00 16.50 17.00 17.50 18.00 18.50 19.00

5000

10000

15000

20000

25000

30000

35000

40000

Time

Abundance

213

1. Disulfoton2. Fenamiphos3. Tribufos (DEF)

Figure 2. Enlarged section of the total ion chromatogram (scan mode) for a 1-L injection of 1.0 g/mL EPA Method 525.2 standard pesticide mix. The peaks noted in the figure are the three organophosphorus pesticides of interest. Chromatographic conditions are listed in Table 1A.

5Figure 3. Total ion chromatogram (scan mode) of the 0.1-ng on-column Ultra Scientific standard solution loading on an Agilent J&W DB-5ms Ultra Inert 30 m 0.25 mm 0.25 m capillary GC column (p/n 122-5532UI). Chromatographic conditions are listed in Table 1B.

5.205.00 5.40 5.60 5.80 6.00 6.20 6.40 6.60 6.80 7.00 7.20

200

400

600

800

1000

1200

1400

1600

1800

Time

Abundance

S/N ratio = 5.33

Peak Height = 1600 abundance units

Noise = 300 abundance units

Figure 4. Enlarged section of the total ion chromatogram (scan mode) for a 1-L injection of 0.1 g/mL Ultra Scientific standard pesticide mix on an Agilent J&W DB-5ms Ultra Inert 30 m 0.25 mm 0.25 m capillary GC column (p/n 122-5532UI). The peak in the figure is mevinphos, an organophosphorus pesticide of interest. This injection represents an on-column loading of 0.1 ng per component. Chromatographic conditions are listed in Table 1B.

6Component R2

Cycloate 1.000Prometon 0.999Disulfoton 0.999Ametryn 0.999Fenamiphos 0.978Tribufos (DEF) 0.997

0.00 5.00 10.00 15.00

Disulfoton

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

Figure 5. Correlation coefficients for the EPA Method 525.2 pesticide components over the 0.1 to 10 g/mL range of this study and an example linear regression plot for disulfoton.

0

2000000

4000000

6000000

8000000

10000000

12000000

14000000

0.00 5.00 10.00 15.00

Mevinphos

Component R2

1,3-Dimethyl-2-nitrobenzene 0.999Mevinphos 0.990Pentachlorophenol 0.989Terbufos 0.996Bromacil 0.988Aldrin 0.999Carboxin 0.996Endrin 0.998p,p'-DDT 0.996Triphenylphosphate 0.997DEHP 0.996

Figure 6. Correlation coefficients for the Ultra Scientific pesticide components over the 0.1 to 10 g/mL range of this study and an example linear regression plot for mevinphos.

Conclusions

This application successfully demonstrates the use of anAgilent J&W DB-5ms Ultra Inert capillary GC column fortrace-level organophosphorus pesticides. Linearity was excel-lent for all organophosphorus pesticides studied, yielding 0.99or greater R2 values down to a 0.1-ng on-column loading ofeach component. One of the reasons for excellent linearityand high R2 values is the highly inert surface of the column.The lack of chemically active sites makes these columns anexcellent choice for trace-level applications.

This study was done using scan mode on an Agilent6890/5975B GC/MSD equipped with an inert electron impactsource. The signal-to-noise ratio for a 0.1-ng on-column load-ing of mevinphos was greater than 5 to 1 with this system.This result shows clearly the power of using an Agilent J&WDB-5ms Ultra Inert column for trace-level organophosphoruspesticides analysis. Lower limits of quantification are expect-ed when using one of Agilent's latest GC/MS offerings, suchas the 7890/5975C GC/MSD Triple-Axis Detector coupledwith an Agilent J&W DB-5ms Ultra Inert GC capillary column.

7References

1. J. Routt Reigart and James R. Roberts, Recognition andManagement of Pesticide Poisoning, 5th Ed, 1999, pp 3447 [Online] Avaliable:www.epa.gov/oppfead1/safety/healthcare/handbook/handbook.htm

2. Kenneth D. Katz, et al, "Organophosphate Toxicity,"[Online]. Available:www.emedicine.com/med/TOPIC1677.HTM (Article lastupdated May 30, 2008)

3. K. Steenland, "Chronic Neurological Effects ofOrganophosphate Pesticides," BMJ, May 25, 1996;312(7042): 1312 1313.

4. J. W. Eichelberger, et al., US EPA Method 525.2 Revision2.0, Determination of Organic Compounds in DrinkingWater by Liquid-Solid Extration and Capillary Column GasChromatography/Mass Spectrometry, National ExposureResearch Laboratory, USEPA, Cincinnati, Ohio, 1995.

5. Mitch Hastings, Allen K. Vickers, and Cameron George,"Inertness Comparison of Sample of 5% Phenyl-dimethylpolysiloxane Columns," Poster Presentation,54th Annual Pittsburg Conference, Orlando, FL, March 2003

6. "Agilent J&W Ultra Inert GC Columns: A New Tool toBattle Challenging Active Analytes," Agilent Technologiespublication 5989-8685EN, May 29, 2008

7. Kenneth Lynam, "Semivolatile Analysis Using anInertness Performance Tested Agilent J&W Ultra InertDB-5ms Column," Agilent Technologies publication 5989-8616EN, May 13, 2008

8. Kenneth Lynam and Doris Smith "Polycyclic AromaticHydrocarbon (PAH) Analysis Using an Agilent J&W DB-5ms Ultra Inert Capillary GC Column," AgilentTechnologies publication 5989-9181EN, in press

For More Information

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Agilent shall not be liable for errors contained herein orfor incidental or consequential damages in connectionwith the furnishing, performance, or use of this material.

Information, descriptions, and specifications in this publication are subject to change without notice.

Agilent Technologies, Inc., 2010Published in the USAMarch 30, 20105989-9879EN

Highly Sensitiveand RuggedGC/MS/MS ToolFor Pesticide Multiresidue Analysis inFood Samples

Agilent 7000 Series Triple Quadrupole GC/MS.The worlds first MS/MS designed specifically

for GC Analysis

Multi-residue methods are efficient and cost-effective for analysis of pesticideresidues. For methods with a very wide scope, generic sample preparation proce-dures are usually employed. Inherent to this approach is that clean up of extracts is only possible to a limited extent1. When applying such methods to complex matrices like baby food, herbs, spices and tobacco, enhanced selectivity in detec-tion is required to make up for the low selectivity in sample preparation.

The analytical challenge is to maximize the number of pesticides, minimize the variety of methods, keep run times short and achieve limits of detection (LODs) at or below the maximum residue limits (MRLs) which are specified for pesticidesunder EU legislation.

As regulations in the European Union require very low MRLs for pesticide residues,the latest challenge has been to reach part-per-billion level concentrations for hundreds of pesticides in complex matrices, which in turn has required greater sensitivity and efficiency in pesticide screening. Quantitation and confirmation ofidentity of trace level compounds can be complicated by the matrix, resulting inqualifier ion ratios out of range, or target ions buried in the high chemical back-ground noise. With single quadrupole mass spectrometry, selected ion monitoring(SIM) is often used to improve the detection limit and quantitative reproducibility. In SIM mode, only a few ions are monitored for each target within the retentiontime (RT) range that the target elutes from the column. SIM may not work well fortrace levels in matrix as the interferences in SIM are the same as in full scan mode.

Triple quadrupole mass spectrometry allows for drastic reduction or elimination ofmatrix interferences that limit the accuracy and detection limits of SIM methods.This process, referred to as Multiple Reaction Monitoring (MRM), has two funda-mental advantages over SIM. First, detection is based secondary product ion pro-duced by the collisional dissociation of an analyte precursor ion. The analyte pre-cursor ion (isolated in Q1 by a SIM mechanism) has the same selectivity as SIM,but there is a high probability that at least one of the resultant product ions will beunique to the precursor and not the interference. The increase selectivity of MRMis often apparent by the reduced offset of the baseline as compared to SIM.Secondly, during the mass filtering process in Q1, all lower m/z ions from the sam-ple are eliminated. The unique product ions from the collisional dissociation aremeasured in this zero noise region of the spectrum. The combination of a uniqueproduct ions (more selectivity) and the elimination of background noise results inconsistently low limits of detection even for complex matrices.

This application brief describes the analysis of pesticides in fruit and vegetableextracts using the Agilent 7000 Series Triple Quadrupole GC/MS system in MRMmode and in combination with Retention Time Locking2 and Agilent Capillary FlowTechnology to provide backflushing of high-boiling materials.3

Introduction

2

Our Integrated Approach

Your Challenges

Column backflushing is essential for the analysis of complex samples such as foodextracts4 because they usually contain high-boiling indigenous compounds. In just a few runs, these materials can collect on the head of the column, causing peaktailing, retention time shifts and increased chemical noise. Over time, they canmigrate from the column to the ionization source, which would eventually have tobe cleaned. Agilent's proprietary capillary flow technology makes column backflush-ing routine and easy to setup for non experts.

The method robustness is drastically increased and the analysis cycles are short-ened5. In conclusion the system up-time is maximized allowing significant produc-

tivity gains. The need for maintenance isreduced by keeping the chromatographicsystem and MS ion source cleanerbetween each injection.

Experimental

Samples were prepared using theQuEChERS6 method. QuEChERS standsfor Quick Easy, Cheap, Effective, Ruggedand Safe and is a food sample prepara-tion for multi-class, multi-residue pesti-cide analysis. See more at www.agilent.com/chem/Quechers

InstrumentationThe Triple quadrupole GC/MS systemused for these experiments are describedin Table 1 and shown in Figure 1.

3

Figure 1Agilent 7890A/7000A Triple Quadrupole GC/MSsystem with the new high capacity 7693 ALS.

InstrumentationGC/MS Triple Quadrupole: Agilent 7000A GC: Agilent 7890AInlet: PTV, in splitless mode, 1L Injection, Multi-baffle liner

80 C for 0.5 min, then 500 C/min to 280 C for 2 min Capillary flow technology device: 3-way splitter with analytical column in and restrictor out to the

triple quadrupole helium pressure provided by Aux EPC at 1 psiColumn: Agilent J&W HP-5ms Ultra Inert 30 m x 0.25 mm ID,

0.25 m HP-5MSUIRestrictor: 80 cm x 0.180 mm deactivated fused silicaCarrier gas: Helium 30.883 psi (constant pressure mode)Oven temperature: 70 C (1 min), 25 C/min to 150 C (0 min), 3 C/min to 200 C (0 min),

8 C/min to 280 C (10 min)Backflush: Time 5 min, inlet press. 1 psi, Aux EPC 80 psi, oven temp. 280 CRetention time locking: Chlorpyrifos-methyl locked to 16.53 minCollision cell gases: N2 2.60 psi and He 6.25 psiInert source temperature: 260 CQuadrupole temperature: 150C

Table 1Instrument conditions.

Instrument conditions

Counts vs. Mass-to-Charge [m/z]

1

0

2

3

4

5

6x103

50 60 70 80 90 100 110 120 130 140 150 170 180 190 200 210160

Method DevelopmentIn order to maximize the response ofthe instrument for each residue thechoice of precursor ion, product ion andcollision energy were optimized. Thespectra of a typical pesticide in fullscan mode (50-500 m/z) e.g. Dicloran(MW = 206) is displayed in Figure 2.The product ion scan spectra of 206m/z at different collision energy aredisplayed in Figure 3.

4

Figure 2Full scan spectrum of Dicloran under EI ionization mode.

Results

Figure 3Product ion scan of Dicloran for the Precursor (206 m/z ) at different collision energies (5-40 V).

Results

The optimum collision energy for the206>176 transition product ion wasfound to be at 10V and the resultingMRM chromatogram is shown in Figure 4.

Results and discussion

Figure 5 shows the TIC chromatogramacquired in MRM mode for 360 pesti-cides. Each MRM segment is indicatedby a grey marker line. An enhancedview on a selected part of the analysiswith an overlay of all MRM for the compounds in this part is shown Figure 6. The MRM mode allows for accurate quantification of manycoeluting analytes as shown between13.6 and 14.2 minutes. Figure 7 demon-strates the identity confirmation ofDiclobenil in a peppermint extract at 10 pg on column using two MRM transitions. The dashed lines indicatethe allowed range of the ion ratio asspecified in the method.

5

Counts vs. Acquisition Time [min]

0.5

1

1.5

2

2.5

3

x106

12.35 12.45 12.55 12.65 12.75 12.85

Figure 4MRM chromatogram of Dicloran at 10ppb.

Results

Counts vs. Acquisition Time [min]4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

x104

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2.0

Figure 5Total ion chromatogram of the vegetable extract by GC/MS/MS.

Results

011.5 11.7 11.9 12.1 12.3 12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3

Counts vs. Acquisition Time [min]

0.8

1,2

1.6

2.0

2.4

x103

0.4

Figure 6Overlay of extracted MRM transitions.

Results

Linearity was also tested with five levels between 1 and 200 ppb for 360pesticides and Figure 8 shows the calibration curves for Diclobenil andChlormefos. The correlation coeffi-cients of the external standard calibra-tion curve were 0.99 on average. TheLOD was estimated based on the calcu-lated S/N of the 10 pg standard. Forthe majority of pesticides, LODs werebelow 2 pg on column (based on S/N>3:1 Peak to Peak).

Retention time reproducibility was alsotested to demonstrate the robustnessof the analytical method. Figure 9shows the outstanding retention timestability of one representative com-pound: Trifluralin. Calculated %RSD is0.0306 at 6.073 min for one hundredconsecutive injections of lettuceextract into the GC/MS/MS system.Only 3 minute Backflush was necessaryto remove all high boiling matrix com-pounds, the total cycle time for this stability test was 21 hours.

6

Dichlobenil7 Levels, 7 Levels Used, 7 Points, 7 Points Used, 0 QCs

Concentration (ng/ml) Concentration (ng/ml)0 20 40 60 80 100 120140160180200

x105 x105

00.2

0.6

1

1.3

1.6

y = 953.8898 * x - 58.7038R2 = 0.99989052

ChlormefosLevels, 7 Levels Used, 7 Points, 7 Points Used, 0 QCs

0 20 40 60 80 100 120 140160180200

0

0.2

0.4

0.6

0.8

1

y = 554.7783 * x - 1176.5985

R2 = 0.99902029

Figure 8Calibration curves showing excellent linearity over the concentration from 1 ppb to 200 ppbrange R2= 0.999 respectively for Dichlobenil and Chlormefos.

Results

6,150

6,130

6,110

6,090

6,070

6,050

6,030

6,010

5,990

5,970

5,9501 11 21 31 41

Injection Number

RT

[min

]

51 61 71 81 91

Min 6.070Max 6.075Mean 6.073Std Devn 0.00186% RSD 0.0306

Figure 9Exceptional retention time stability of Trifluralin with 100 injections of lettuce extract thanks tocolumn backflushing.

Results

Coun

ts

Acquisition Time [min]6 6.4 6.8 7.2 7.6

x102

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4Ratio=80.7171.0 -> 136.0, 171.0 -> 100.0

Figure 7Two transitions identifying Diclobenil in a peppermint extract at 10 pg on column.The dashed lines indicate the allowed rangeof the ion ratio.

Results

Conclusion

Agilents 7000 Series TripleQuadrupole GC/MS in combinationwith the 7890 GC is a sensitive andrugged tool for target pesticide analy-sis in complex matrices. The singlemulti-residue method we developedalso meets the performance and iden-tity confirmation criteria defined bythe stringent EU regulations.

Excellent selectivity has beenachieved to allow unambiguous con-firmation of identity for these 360 pes-ticides even in very complex foodmatrices and generic sample cleanup. Agilent SampliQ QuEChERS kitsenable you to prepare food samplesfor multiresidue, multi-class pesticideanalysis with just a few simple steps.

For this new GC/MS/MS method, theAgilent Retention Time Locking (RTL)database was used to calibrate theretention times of all pesticides.Therefore, the presented GC/MS/MSmethod can be easily transferred toother Agilent 7000 Series TripleQuadrupole systems with minimumeffort and time.

7

References

1. M. Mezcua, M. A. Martnez-Uroz, P. L.Wylie, and A. R. Fernndez-Alba,Simultaneous screening and targetanalytical approach by GC-q-MS forpesticide residues in fruits and vegeta-bles, Accepted for publication by J.AOAC Int.

2.Bruce D. Quimby, Leonid M. Blumberg,Matthew S. Klee, and Philip L. Wylie,Precise Time-Scaling of GasChromatographic Methods UsingMethod Translation and Retention TimeLocking, Agilent Technologies publica-tion 5967-5820E.

3.Capillary Flow Technology, more information at http://www.agilent.com/chem/cft

4.Chin-Kai Meng Improving Productivityand Extending Column Life withBackflush, Agilent Technologies publi-cation 5989-6018EN.

5.Chris Sandy Improving GC-MS MethodRobustness and Cycle Times UsingCapillary Flow Technology andBackflushing Agilent Technologiespublication 5990-3367EN.

6.Limian Zhao, Joan Stevens Analysis ofPesticide Residues in Spinach UsingAgilent SampliQ QuEChERS AOAC Kitsby GC/MS Agilent Technologies publi-cation

www.agilent.com/chem/7000B

Agilent Technologies, Inc., 2009Published November 1, 2009Publication Number 5990-5044EN

A Method for the Trace Analysis of175 Pesticides Using the AgilentTriple Quadrupole GC/MS/MS

Abstract

A GC/MS/MS multiple reaction monitoring (MRM) method has been developed on

the Agilent 7890A/7000A GC triple quadrupole mass spectrometer system (GC/QQQ)

for 175 commonly analyzed pesticides. Numerous fruit and vegetable extracts were

analyzed by this method and by a GC single quadrupole mass spectrometer (GC/Q) for

comparison. The GC/Q was operated in the selected ion monitoring (SIM) mode and

in the scan mode. Scan results were evaluated using Agilent's Deconvolution

Reporting Software (DRS) with the RTL Pesticide and Endocrine Disruptor Database.

The GC/Q instrument was equipped with a Multimode inlet and injections of 5 L

were made in the cold splitless mode. These were compared to 1 L injections of the

same extracts on the GC/QQQ. The GC/QQQ was found to be far more sensitive and

selective than either GC/Q approach, primarily because there is much less interfer-

ence from co-extracted matrix. There is, however, still a need for GC/Q methods that

use DRS to screen for more than 900 pesticides and other contaminants since the

GC/QQQ in the MRM mode is only for target compound analysis.

Authors

Philip L. Wylie and Chin-Kai Meng


2850 Centerville Rd.


USA

Application NoteFood Safety

2Introduction

Pesticide residue analysis is a complex task requiring the ana-lyst to search for dozens, or even hundreds, of compounds in awide variety of crop matrices. Extraction techniques, such asthe QuEChERS method [13] leave large amounts of indige-nous materials in the extract. The use of more extensivecleanup steps risks removing pesticide residues in addition tothe matrix. As required detection limits for many pesticides fallto 10 g/Kg (10 ppb) or lower, more sophisticated analyticaltools are needed.

For GC-amenable pesticides, many laboratories are using twocomplementary techniques for screening and confirmation pur-poses. For broad screening at the 5 to 100 ppb level, GC/singlequadrupole (GC/Q) is employed with Deconvolution ReportingSoftware (DRS) and the RTL Pesticide and Endocrine Disruptorlibrary from Agilent Technologies [46]. This is a scan methodto screen for 927 GC-amenable pesticides and endocrine dis-ruptors in a single GC/MS run. Detection limits for most pesti-cides vary from approximately 5 to 100 ppb, depending uponthe matrix and the injection volume [4]. For target pesticideanalysis in the most complex matrices, the Agilent 7890A/7000A GC/triple quadrupole (GC/QQQ) is unmatched.

This paper compares three mass spectral techniques for theanalysis of pesticide residues in a variety of crop matrices.Spiked and unspiked samples were analyzed by GC/Q in theselected ion monitoring (SIM) mode and in the scan mode withDRS analysis. The same samples were also analyzed byGC/QQQ using a multiple reaction monitoring (MRM) methodfor 175 pesticides. The objective was to compare the ability ofthese GC/Q and GC/QQQ methods to detect low levels of pes-ticides in several different crop matrices.

Experimental

Samples

Spiked and unspiked extracts of fresh produce were providedby the U.S. Food and Drug Administration (U.S. FDA, CFSAN,College Park, MD) and the U.S. Department of Agriculture(USDA ARS, ERRC, Wyndmoor, PA). Samples from the FDAwere prepared using the QuEChERS [13] method modified toinclude the use of activated carbon as an additional sorbent.The resultant toluene solution contained 4.5 grams of produceper milliliter of extract. Samples from the USDA were extractedusing the published QuEChERS method and contained 1 gramof produce per milliliter of acetonitrile solvent.

Instrumentation

The GC/Q and GC/QQQ systems used for these experimentsare described in Tables 1 and 2.

Table 1. Instrumentation and Analytical Conditions for the GC/Q System

GC Agilent 7890A SeriesAutosampler Agilent 7693A Injector and sample trayInlet Multimode inletCarrier gas HeliumInlet pressure 18.420 psi (constant pressure mode) during run

2.0 psi (during backflush)

Splitless Mode Inlet ParametersTemperature 250 CInlet liner Helix double taper, deactivated (P/N 5188-5398)Injection volume 1 LPurge flow to split vent 30 mL/min at 0.75 min

Cold Splitless Mode Inlet ParametersTemperature program 60 C (0.01 min), 700 C/min to 280 C (hold)Inlet liner Helix double taper, deactivated (P/N 5188-5398)Injection volume 5 L Purge flow to split vent 30 mL/min at 1.25 min

Oven temperature program 70 C (1 min), 50 C/min to 150 C (0 min),6 C/min to 200 C (0 min), 16 C/min to 280 C (5 min)

Capillary flow technology 2-way splitter with one port capped used forbackflushing the analytical column and reten-tion gap

Pneumatic Control Module Helium plumbed to 2-way splitter(PCM)PCM pressure 4.0 psi during run, 60.0 psi during backflush Analytical column Agilent J&W HP-5ms UI 15 m 0.25 mm

0.25 m (P/N 19091S-431UI)Connections Between retention gap and 2-way splitter

Retention gap 2.0 m 0.25 mm Siltek deactivated fused silicatubing (Restek, Bellefonte, PA)

Connections Between inlet and analytical column using anUltimate Union (P/N G3182-61580) to couple the retention gap to the column

Restrictor 80 cm 0.15 mm deactivated fused silica tubing (Agilent)

Connections Between the 2-way splitter and the MSDInitial column flow rate 2.705 mL/min (nominal)Retention time locking Chlorpyrifos-methyl locked to 8.298 minMass selective detector Agilent 5795C Series with performance turbo

pumpMode Electron impactTransfer line temperature 280 CSource temperature 230 CQuadrupole temperature 150 CThreshold 100Sampling rate A/D = 4Gain factor 1SIM dwell times Variable from 4 to 25 msTrace ion detection OnSolvent delay 2.5 min

Backflushing ConditionsTiming 5 min duration during post-run Oven temperature 280 C

(Continued)

3Results and Discussion

GC Configuration

Both GC systems used a 15-m 0.25 mm 0.25 m AgilentJ&W HP-5ms UI column and were running the standardAgilent pesticide method [7] at 2X speed. This method usesan initial oven temperature of 70 C, which works for most GCsolvents without using a retention gap. However, 1-L injec-tions of samples in toluene lead to poor peak shape, so a 2-mdeactivated retention gap was coupled to the front of the col-umn. This improved the peak shapes.

Column backflushing is essential for the analysis of foodextracts [4, 89] because they usual

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