Pesticides metabolites, emphasis

Pioneers in the use of plant cell systems for studies of xeno-biotic phytotoxicity and metabolism have laid the groundwork for an increasing number of researchers interested in the advantages the cell systems offer (4 6-9). Greater emphasis on the identification of pesticide metabolites formed in whole plants and cell cultures has made evaluation of both systems more meaningful. Although the literature is nearly devoid of studies concerning diaracterization of enzyme systems from plant cell cultures that may be responsible for pesticide metabolism reference to the cell cultures as a convenient source has been made (10). 

Space does not permit further discussion of the fate of various organic pesticides in mans environment. Some of the fate reactions involving the older pesticides have been extensively studied, but the picture is far from complete, even for such compounds as DDT and parathion. However, increasingly greater emphasis on more fundamental research is being made, particularly with the recently introduced pesticides, to determine all their possible metabolites under varying environmental conditions. 

This chapter will discuss the role of contemporary GC in biochemistry. Due to the very rapid proliferation of this technique into various branches of science that could be considered biological , it is virtually impossible to review comprehensively all applications. Thus, considerable emphasis will be placed on the most important developments of the last decade, stressing the principles and fundamental directions. The major classes of metabolically important compounds will be treated individually, while the most useful applications will be referred to. In general, man-made chemicals (such as pesticides, drugs and their metabolites) have been excluded from this discussion. 

This chapter focuses on LC—MS/MS applied to pesticide residue analysis, as this technique is the most attractive and efficient nowadays for developing MRMs [11], including both parent pesticides and metabolites. Sample treatment (mainly extraction and cleanup) are briefly commented on, with emphasis on those commonly applied in MRMs. A brief mention is made of problematic pesticides that do not fit in MRMs and consequently need to be determined with individual-specific LC—MS/MS methods. The use of HR MS in combination with LC also is briefly treated, either for the investigation of parent pesticides or for metabolite research, as this is a field of major interest at present. 

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