Environmental and food applications of LC–tandem mass spectrometry in pesticide‐residue analysis: An overview

Abstract

I.Introduction45 II.Pesticide Structures and Properties46 III.Extraction and Isolation Methods from Environmental and Food Samples47 IV.LC/MS/MS Analysis of Pesticides53A. Interfacing Systems53B. Instrumental Aspects57C. Optimization of Chromatographic Mass Spectrometric Conditions57 V.Tandem MS Methods59A. Triple Quadrupole59B. Quadrupole Ion Trap66C. Hybrid Quadrupole TOF (Q‐TOF)71 VI.Performance Characteristics of LC‐Tandem MS for Pesticides72 VII.Applications75 VIII.Conclusions80References81 An overview is given on pesticide‐residue determination in environmental and food samples by liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Pesticides comprise a large number of substances that belong to many completely different chemical groups, the only common characteristic is that they are effective against pests. They still constitute a challenge in MS because there is no collective pathway for fragmentation. A brief introduction to the theory of tandem MS permits a discussion of which parameters influence the ionization efficiency when the ions are subjected to different actions. Emphasis is placed on the different tandem MS instruments: triple and ion‐trap quadrupoles, and hybrid quadrupole time‐of‐flight (Q‐TOF), including advantages and drawbacks, typical detection limits, and ion signals at low concentrations. The instrumental setup, as well as LC and mass spectrometric experimental conditions, must be carefully selected to increase the performance of the analytical system. The capacity of each instrument to provide useful data for the identification of pesticides, and the possibility to obtain structural information for the identification of target and non‐target compounds, are discussed. Finally, sample preparation techniques and examples of applications are debated to reveal the potential of the current state‐of‐the‐art technology, and to further promote the usefulness of tandem MS. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 23:45–85, 2004

Aspectos analíticos e regulatórios na determinação de resíduos de macrolídeos em alimentos de origem animal por cromatografia líquida associada à espectrometria de massas

“…A diferença de potencial oscilante entre o anel e os eletrodos hiperbólicos gera um campo magnético capaz de confinar ou deixar passar os íons. 77,78 Este tipo de analisador tem a característica única de conduzir fragmentações em múltiplos estágios (MS n ). Quando os íons entram no ion-trap, todas as fragmentações ocorrem no mesmo local, mas em tempos diferentes, apresentando melhor sensibilidade na varredura do que os QqQ, mas com a limitação de não realizar aquisições alternadas entre os modos de varredura do íon produto e de varredura de perda neutra.…”

“…Quando os íons entram no ion-trap, todas as fragmentações ocorrem no mesmo local, mas em tempos diferentes, apresentando melhor sensibilidade na varredura do que os QqQ, mas com a limitação de não realizar aquisições alternadas entre os modos de varredura do íon produto e de varredura de perda neutra. 77,79 Além disso, estes instrumentos são menos robustos para análise de matrizes mais complexas e podem apresentar baixa repetibilidade e faixa dinâmica muito estreita para a quantificação. 80 Instrumentos do tipo QIT têm sido usados para caracterizar os padrões de fragmentação de macrolídeos como a azitromicina.…”

Empleo de la espectrometría de masas como herramienta para la determinación de tóxicos en alimentos: hacia la seguridad alimentaria

“…Si operan en modo "barrido completo" o "full scan", los voltajes aplicados varían en función del tiempo para obtener un espectro de masas del compuesto, proporcionando información muy precisa relacionada con la identidad del producto. Sin embargo, también se puede fijar un voltaje determinado seleccionando así un solo ión, originando una excelente sensibilidad con una alta especificidad, siendo ideal con fines cuantitativos de trazas y ultratrazas 15 .…”

Development and validation of a method using SPE and LC-ESI-MS-MS for the determination of multiple classes of pesticides and metabolites in water samples

“…Since the beginning of its development, agriculture has been directly related to pesticide application: it stands out as the main way to control pests, plagues and weeds which attack agricultural products, harming crops and reducing productivity. 1,2 On one hand, pesticides play an important role in protecting crops, but, on the other hand, its indiscriminate use continues to cause many serious problems for the environment and human health. [3][4][5] Nowadays, pesticide monitoring in waters, both in natural ones and in the ones destined for public supply, is a major issue.…”

“…It supplies quantitative and qualitative information about the compounds that are eluted from the column, and it can distinguish different substances with the same retention time. 2,40 Due to the low detection levels required by regulatory bodies and the complex nature of the matrices in which the target compounds are present, efficient sample preparation and trace-level detection and identification are important aspects of analytical methods. Sample preparation, such as extraction, concentration and isolation of analytes, has great influence on the reliability and the accuracy of the analysis.…”