Development of a hydrazinolysis method for the determination of vinclozolin in foods by SPE and GC-MS/MS

This study presents the first application of hydrazinolysis for determining total vinclozolin (VZ) residues, including 3,5-dichloroaniline (3,5-DCA)-containing metabolites. Based on the Gabriel synthesis mechanism, target analytes were selectively converted to 3,5-DCA. Unlike conventional alkaline hydrolysis or separate analyte detection, this approach employed mild derivatization with minimal reagent consumption (0.02 mL hydrazine hydrate per sample), followed by solid-phase extraction (SPE) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Validated per SANTE/11312/2021v2 guidelines across eight matrices, the method showed excellent linearity (R² ≥ 0.998), accuracy (73.5-96.8% recovery), and precision (RSDs ≤16.5%), with LOQs of 0.02 mg/kg-fully compliant with the regulatory residue definition (sum of VZ and all 3,5-DCA-containing metabolites). Kinetic analysis further elucidated that structural analogs like iprodione exhibited lower conversion due to steric hindrance. This streamlined workflow drastically reduces sample preparation time and eliminates hazardous reagents, offering a practical, high-throughput solution for modern food safety monitoring of VZ.