Fast Gas Chromatography and Its Use in Pesticide Residues Analysis

Abstract

Pesticides have been worldwide used for the protection of food crops against pests and diseases. It is common that residues of these pesticides occur in food products, especially agricultural commodities. Adverse effects on human health of pesticides residues remaining in food after they are applied to food crops are generally known. Possible health risk due to pesticide residues in the diet has deeply modified the strategy for the crop protection, with emphasis on food quality and safety. The widespread concern for the health of society led to the strict regulation of maximum residue limits (MRLs) of pesticide residues in food commodities. There are various organizations that set maximum residue limits (MRLs), such as European Commission (EC), Codex Alimentarius or national governments in Australia, Canada, Japan, USA, etc. Individual limits for different active substance per food commodity combinations are being set by EC within the range of 0.0008-50 mg.kg-1 (Directive 91/414/EEC). Newly discovered ecotoxicological problems, particularly the knowledge on endocrine disrupting effects (Colborn et al., 1993; Lintelmann et al., 2003) related also to pesticide residues, emphasise the acute requirement of analytical methods development with increased sensitivity and reliability for monitoring, confirmation and quantification of lower residue levels. Analysis close to these levels corresponds to the ultratrace analysis. This calls for urgent attention in two areas: (a) legislative requirements continuously decreasing the maximum acceptable concentration levels in food, and (b) the apparent importance of methods development in the area of pesticide residues analysis. The urgent requirement for low-level analyses promotes also contribution to the science – in the field of separation methods for ultra-trace analysis of organic pollutants in complex mixtures. The method development heads to speeding up the analysis (what leads to reduction of financial demands) while preserving the efficiency of conventional approaches or getting even better efficiency. In pesticide residues analysis additionally there is ever increasing interest to analyse as many analytes as possible in a single analysis. In the case of semivolatile pesticide residues analysis gas chromatography (GC) still plays an important role. Scientifically valid methods for the analysis at low concentration levels are currently still often very close to limits of detections (LODs). The most efficient approach to pesticide analysis involves the use of multiclass, multiresidue methods (MRMs). The sample preparation procedure should be taken into consideration together with the chromatographic analysis and detection in many aspects, mainly in limit of quantifications (LOQs) and selectivity. In multiresidue pesticides analysis used for an inspection of the