LC-MS/MS analysis of polar pesticides in mango: enantiomers, docking, and retention mechanisms

A simple, eco-friendly LC-MS/MS method was developed for the simultaneous analysis of 14 highly polar analytes, including six parent pesticides and eight metabolites, in mango. Using pure water for extraction and an ion chromatography column, the method achieved excellent linearity (R > 0.995), low limits of quantitation (LOQs, 10-50 μg kg^-1), and satisfactory recoveries (72.3%-115%). Molecular docking elucidated the retention mechanism, revealing a strong positive correlation (R² > 0.912) between calculated binding free energies and experimental retention times. The successful enantioselective separation of glufosinate ammonium was attributed to subtle differences in binding free energies between its enantiomers and the stationary phase, driven by electrostatic and hydrogen-bonding interactions. The method's practicality was confirmed by detecting four compounds in commercial mangoes. This work provides a reliable tool for monitoring polar pesticides and offers a new mechanistic perspective for developing chromatographic methods for challenging analytes.