Response surface methodology for the enantioseparation ofdinotefuran and its chiral metabolite in bee products andenvironmental samples by supercritical fluidchromatography/tandem mass spectrometry
Abstract
Tracing the enantiomers of dinotefuran and its metabolite in bee products and relevant environmentalmatrices is vital because of the high toxicity of their racemates to bees. In this study, a statistical opti-mization strategy using three-dimensional response surface methodology for the enantioseparation ofdinotefuran and its metabolite UF was developed by a novel supercritical fluid chromatography/tandemmass spectrometry (SFC–MS/MS) technique. After direct evaluation of the chromatographic variables– co-solvent content, mobile phase flow rate, automated backpressure regulator pressure (ABPR), andcolumn temperature – involved in the separation mechanism and assessment of the interactions amongthese variables, the optimal SFC–MS/MS working conditions were selected as a CO2/2% formic acid-methanol mobile phase, 1.9 mL/min flow rate, 2009.8 psi ABPR, and 26.0?C column temperature using anamylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase under electrospray ionization pos-itive mode. Baseline resolution, favorable retention, and high sensitivity of the two pairs of enantiomerswere achieved in pollen, honey, water, and soil matrices within 4.5 min. Additionally, the parametersaffecting the dispersive solid-phase extraction procedure, such as the type and content of extractant orpurification sorbents, were systematically screened to obtain better extraction yields of the enantiomers.Mean recoveries were between 78.3% and 100.2% with relative standard deviations lower than 8.0% inall matrices. The limits of quantification ranged from 1.0 g/kg to 12.5 g/kg for the dinotefuran and UFenantiomers. Furthermore, the developed method was effectively applied to authentic samples from amarket, an irrigation canal, and a trial field, and the enantioselective dissipation of dinotefuran and UFin soil was demonstrated.
