Enantioselective high-performance liquid chromatographic separations to study occurrence and fate of chiral pesticides in soil, water, and agricultural products

As many as 40% of all plant protection products currently used contain chiral active ingredients. Enan-tiomers of the same pesticide have identical physicochemical properties in an isotropic medium, but they may display different activity and toxicity because of their interaction with enzymes or other naturally occurring asymmetric molecules. This difference may also lead to variations in biotic degradation rates, making one enantiomer more persistent than the other in natural and agricultural environments.In terms of methodological aspects, this critical review describes the most used chiral stationary phases for HPLC enantioseparations of chiral pesticides, pinpointing their strengths and weaknesses. As far as their applicability is concerned, most research has been carried out by means of columns based on derivatized amylose/cellulose due to their rather universal analyte coverage. The chromatographic com-patibility with sensitive detection techniques, such as mass spectrometry, has allowed the trace analysis of stereoisomers, revealing ubiquitous occurrence of some chiral pesticides in surface waters, sediments, plants, agricultural soils, roots, fruit and vegetables. The study of their distribution and degradation in various environmental compartments and agricultural soil-plant systems has highlighted the enrichment with one enantiomer over the other in certain matrices following the enantioselective dissipation catal-ysed by microorganisms or plant enzymes as well as the phenomenon of chiral inversion in some cases.Irrespective of the reliability of a chiral method, such investigations are often hindered by the lack of pure standards of single enantiomers, which makes it difficult to identify their stereochemical configu-ration and requires precise strategies of quantification. Surely, the research in this field has been grown over the last few years due to the necessity of assessing and limiting risks related to exposure to chiral pesticides, which can be considered emerging contaminants in all aspects.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Up to 40% of plant protection products currently used contain chiral active ingredients, which may exhibit different activity, toxicity, and biotic degradation rates due to their interaction with enzymes or other naturally occurring asymmetric molecules. High-performance liquid chromatography (HPLC) is commonly employed for enantioseparations of chiral pesticides, with derivatized amylose/cellulose-based columns being the most widely used due to their universal analyte coverage. Trace analysis using sensitive detection techniques such as mass spectrometry has revealed the ubiquitous occurrence of chiral pesticides in various environmental matrices. The research in this field has grown significantly in recent years, driven by the need to assess and mitigate the risks associated with exposure to these emerging contaminants.