Chiral Pesticides

Abstract

The use of pesticides for industrial and domestic purposes has increased tremendously in recent years. Herbicides, fungicides, pyrethroids, and organophosphates are among the pesticides that are widely used. Most of these pesticides have one or more asymmetric chiral atoms, and therefore, they exhibit stereoisomerism. Often, these chiral pesticides are sold as racemates. The enantiomers in the racemates usually have different toxicity to both target and non-target organisms. Sometimes, only one enantiomer is active, and the other ones are less or not active but toxic to non-target organisms. Detailed examples to show the enantioselective toxicity of chiral pesticides to both target and non-target organisms are given in this chapter. The need for assessment of the environmental impact of chiral pesticides should not be overemphasized. Monitoring of chiral pesticides in the environment can be done using chiral separation techniques such as chiral high-performance liquid chromatography, chiral gas chromatography, chiral capillary electrophoresis, and chiral supercritical fluid chromatography. Thus, this chapter discusses the enantioselective analytical methods that have been developed to enable separation and identification of enantiomers of chiral pesticides. The enantiomers of chiral pesticides can have detrimental effects to the environment even at trace concentrations. Consequently, pre-concentration techniques such as dispersive liquid-liquid micro-extraction, QuEChERS, liquid-liquid extraction, and SPE are sometimes employed to enable trace analysis of chiral pesticides and their applications during chiral pesticide analysis are discussed in this chapter.