Multiclass, Multiresidue Analysis of Pesticides, Strategies for

Abstract

Strategies for multiclass, multiresidue analysis of pesticides depend on several factors that all derive from three fundamental considerations: (1) the need for the results; (2) the form and composition of the matrix; and (3) the time, resources, and technology available to the analyst. First, the need for the data dictates the quality assurance (QA)/quality control (QC) guidelines and the desired analytical figures of merit, such as limits of detection (LOD) and the accuracy and precision of the results. These needs also contribute to the choice of pesticide analytes, which sets the polarity range for the analysis. No single method can determine all pesticides in diverse matrices, so an overall strategy is often used to compartmentalize a series of approaches in order best to detect the targeted pesticides in an effective and efficient process. Second, the various types of matrices that are commonly analyzed for pesticide residues may affect the sample preparation approach employed in the analytical strategy. Common matrices for pesticide analysis consist of solids, liquids, and gases in applications associated with food, agricultural, environmental, and other sample types. Varying degrees of pesticide–matrix interactions in different materials require more or less stringent extraction procedures to separate the pesticides from the sample. Sample preparation in multiclass, multiresidue strategies frequently utilizes liquid–solid, liquid–liquid and other partitioning processes including those, such as pressurized fluid extraction (PFE), in which pressure and temperature of different fluids are controlled. Extracts often require cleanup to remove interfering co‐extracted matrix components prior to analysis. A variety of cleanup techniques based on a number of partitioning processes, such as liquid chromatography (LC), may be employed in an on‐line or off‐line fashion. Lastly, the sample extract is usually further separated and analyzed using one or more techniques. The majority of pesticides are analyzed by gas chromatography (GC) with mass spectrometry (MS) and/or element‐selective GC detectors. High‐performance liquid chromatography (HPLC) is often used in the analysis of thermally labile pesticides that are not amenable to GC analysis. Other alternatives for analysis of certain pesticide include capillary electrophoresis (CE) and immunoassays. Fundamentally, a high degree of selectivity helps in generating excellent analytical results, but the wide polarity range of analytes in multiclass, multiresidue methods (MRMs) for pesticides necessitates a great deal of effort to attain a high degree of selectivity. Trade‐offs and compromises are omnipresent in multiclass, multiresidue analysis of pesticides, and a host of strategies are available depending on how the analytical chemist prioritizes the analytical and practical considerations.

Removal of Organophosphorus (OP) Pesticide Residues from Vegetables Using Washing Solutions and Boiling

“…Neurotransmitters such as acetylcholine (which is affected by organophosphate pesticides) are profoundly important in the brain's development, and many OPs have neurotoxic effects on developing organisms, even from low levels of exposure. In non fatty foods, OPs are detected more frequently than the Organochlorines (OCs) and their residue concentration is typically slightly higher, whereas its opposite is true in case of fatty foods (Lehotay, 2006).…”

Simultaneous Screening of 322 Residual Pesticides in Fruits and Vegetables Using GC-MS/MS and Deterministic Health Risk Assessments

“…Individual methods are highly reliable because the analysis is optimized for individual compounds; however, these methods are less frequently applied for pesticide residue analysis, owing to the time and cost required for detecting multiple pesticides [ 10 , 11 ]. In contrast, MRMs aim to analyze different classes of pesticides in a single analysis, which is conducive for the rapid processing of a large number of agricultural products [ 8 , 12 ]. Based on this efficiency, MRMs are mainly used in the routine monitoring of various pesticide residues and are widely used worldwide for the safety management of pesticide residues [ 13 , 14 ].…”

Screening of multiclass pesticide residues in maca and Moringa oleifera by a modified QuEChERS sample preparation procedure and UPLC-ESI-MS/MS analysis

“…The emergence of new pesticides, instruments and techniques has brought both opportunities and challenges. 26 QuEChERS is not just a method or a pair of official methods (AOAC2007.01 and EN 15662), but it is also a exible approach for chemical sample preparation that is being used in multiple applications. 27 In order to improve the recovery rate and detection efficiency as much as possible, researchers have made a variety of improvements to the QuEChERS method.…”