Large Scale Pesticide Multiresidue Methods in Food Combining Liquid Chromatography- Time-of-Flight Mass Spectrometry and Tandem Mass Spectrometry

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• 作者：Juan F. Garcí ; a-Reyes ; M. Dolores Hernando ; Carmen Ferrer ; Antonio Molina-Dí ; az ; Amadeo R. Fern&aacute ; ndez-Alba
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：October 1, 2007
• 年：2007
• 卷：79
• 期：19
• 页码：7308 - 7323
• 全文大小：376K
• 年卷期：v.79,no.19(October 1, 2007)
• ISSN：1520-6882

文摘

Liquid chromatography tandem mass spectrometry(LC-MS/MS) and liquid chromatography time-of-flightmass spectrometry (LC-TOFMS) are powerful and complementary techniques that can independently cover themajority of the challenges related with pesticide residuefood control. The sequential combination of both systemsbenefits from their complementary advantages and assiststo increase the performance and to simplify routine largescale pesticide multiresidue methods. The proposedapproach consists of three stages: (1) automated pesticide screening by LC-TOFMS; (2) identification by LC-TOFMS accurate mass measurements; and (3) confirmation and quantitation by LC-MS/MS. We have developeda fast comprehensive (identification/confirmation + quantitation) automated screening method for 100 targetpesticides in crops. In the first stage, a set of dataincluding m/z accurate mass windows (within 20 mDawidth) and retention time is obtained (using a standardsolution containing all the targeted pesticides) in orderto build the automated screening procedure, which iscreated automatically by assigning retention time and them/z mass window for each target pesticide. Samples arethen analyzed, and the method enables the screening andpreliminary identification of the species first by retentiontime and m/z mass window, followed by subsequentidentification (only if positive results) by LC-TOFMSaccurate mass measurements. After that, final confirmation of the positive findings using two MRM transitionsand accurate quantitation is performed by LC-MS/MSusing a hybrid triple quadrupole linear ion trap (QqLIT)mass spectrometer. In addition, the use of this QqLITinstrument also offers additional advantageous scanningmodes (enhanced product ion and MS³ modes) forconfirmatory purposes in compounds with poor fragmentation. Examples of applications to real samples show thepotential of the proposed approach, including the detection of nonselected "a priori" compounds as a typical caseof retrospective evaluation of banned or misused substances.