Separation-free enantiodiscrimination of chiral pesticides via dual-stereocenter 19F NMR probes for multicomponent and environmental analysis

Abstract

Background

Chiral pesticides are increasingly important in agrochemicals, with enantiomers differing significantly in bioactivity, toxicity, and environmental impact. Rapid and robust methods for resolving these enantiomers in complex matrices are essential for regulatory monitoring and mechanistic studies.

Results

We developed a separation-free ¹⁹F NMR chemosensing platform using dual-stereocenter ¹⁹F-labeled Pd probes. The method enables direct enantiodifferentiation of N-heterocyclic pesticides, including complex cases like difenoconazole where all four stereoisomers are fully resolved in a single ¹⁹F spectrum. Quantitative enantiomeric excess (ee values) determination shows excellent linearity, with deviations from the true ee values of less than 2 %. The platform also resolves six pesticides simultaneously in a mixture and, in soil extracts, monitors in situ stereoselective degradation, revealing significant degradation bias between enantiomers.

Significance

Dual-stereocenter ¹⁹F NMR probes deliver a practical alternative to chiral chromatography for pesticide residue analysis, combining operational simplicity, matrix tolerance, multicomponent capability, and quantitative rigor. The method enables direct, separation-free readout of stereochemistry and kinetics in complex samples and reveals in situ enantioselective degradation pathways. These attributes provide actionable insight for precision application, environmental risk assessment, and regulatory surveillance of chiral agrochemicals.