Novel application of reversed-phase high performance liquid chromatography-tandem mass spectrometry for enantioselective determination of cyclaniliprole enantiomers in plant-derived foods.

Herein, a rapid and highly sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established and validated for the enantioselective determination of cyclaniliprole (CYCP) enantiomers in diverse plant-derived matrices including fruits (citrus, apple), vegetables (cabbage, tomato) and cereals (corn, soybean) matrices. The key innovation of the present work involves the first successful implementation of baseline enantiomeric separation of CYCP under basic reversed-phase conditions. By systematically screening five different chiral stationary phases and critically evaluating both acidic and basic mobile phases, basic conditions utilizing 0.05% diethylamine aqueous solution and acetonitrile were found to be pivotal. This novel basic reversed-phase system on a Superchiral® R-IC column not only afforded baseline separation within 6.5 min but also significantly enhanced both chiral resolution and elution efficiency, markedly reducing retention times compared to acidic conditions. A simple and effective reversed-phase dispersive solid-phase extraction (r-DSPE) procedure, employing multi-walled carbon nanotubes (MWCNTs) as purification sorbents, was optimized for sample preparation, with systematic evaluation of MWCNT type and quantity on purification efficiency and recovery. Comprehensive method validation was performed for linearity, accuracy, precision, sensitivity (LOQ), matrix effects, and stability. Under optimum conditions, mean recoveries for both enantiomers across all matrices ranged from 74.1% to 103.5% with RSDs < 15.2%. Excellent linearity (r ≥ 0.9991) was demonstrated over 0.5-500 μg/L using weighted (1/x) least squares regression. The LOQ was established at 0.005 mg/kg for both enantiomers in all six matrices. Validation data, coupled with successful application to the analysis of real samples confirming method applicability, demonstrate that this robust protocol is suitable for the enantioselective determination of CYCP residues in various agricultural produce, offering a streamlined solution for monitoring chiral pesticides.