Enantioselective analysis of pesticides in food, biological, and environmental samples by chromatographic techniques and capillary electrophoresis

The use of pesticides such as herbicides, insecticides, and fungicides, has increased due to the high demand for food production. A significant percentage of pesticides are chiral, and their desired activity can reside in one of the stereoisomers being the other(s) inactive or having a lesser activity. In these cases, it would be desirable using pesticides as pure stereoisomers to have the desired activity avoiding the presence of higher amounts of pesticides than those required to obtain the intended effect. However, chiral pesticides are usually commercialized as racemic mixtures causing higher potential harmful effects for the environment and nontarget organisms than if a pure stereoisomer that exhibits the main desired activity would be used. Different metabolism and degradation, dissipation, and toxicological activity are also observed depending on the stereoisomer. Therefore, efficient, selective, and sensitive analytical methods enabling the enantioselective determination of pesticides are required for residue analysis in food, biological and environmental samples. These methodologies are also powerful tools to control the production of agrochemical formulations or evaluate the ecotoxicity of pesticides on nontarget organisms at enantiomeric level. Various separation techniques as liquid chromatography, gas chromatography, supercritical fluid chromatography, and capillary electrophoresis have been employed for this purpose. Current trends in chiral separation techniques applied for the enantioselective analysis of herbicides, fungicides, and insecticides, including pyrethroids, in food, biological and environmental samples are provided in this review covering the period from 2019 to 2023.