Chapter 13 - Multiresidue methods for pesticides and related contaminants in food

Abstract

Pesticide residue analysis is a specialized field of analytical chemistry, where the role of liquid chromatography-mass spectrometry (LC-MS) is of great importance. A highly reliable determination, including both quantification and identification, of pesticide residues in food is required nowadays because of the strict international regulations on maximum residue limits. The increasing interest of including metabolites in analyses comes from the inclusion of pesticide-related compounds within the residue definition. The polar character of most pesticides used at present and particularly of their metabolites make liquid chromatography (LC) coupled to tandem mass spectrometry (MS) the technique of choice for the great majority of compounds. Thus, liquid chromatography tandem mass spectrometry (LC-MS/MS) with triple quadrupole analyzer is highly appropriate for developing multiresidue methods, where up to 300–400 analytes can be simultaneously determined. It can also be efficiently applied to problematic, highly polar, pesticides, although they require specific LC-MS/MS methods, including differentiated sample treatment and measurement conditions. High-resolution MS using modern analyzers such as time-of-flight or orbitrap offer interesting features for wide-scope screening of pesticides and metabolites in food due to the accurate-mass full-spectrum acquisition, with the advantage that a retrospective analysis is feasible at any time to search for other compounds that were not included in the first analysis.