Determination of Butachlor and Fipronil in Liquid Milk Using Ionic Liquid Dispersive Liquid-Liquid Microextraction Coupled with Ultra-High Performance Liquid Chromatography

摘要

A novel method for the determination of butachlor and fipronil in liquid milk has been developed using ionic liquid dispersive liquid-liquid microextraction coupled with ultra-high performance liquid chromatography (UHPLC). The optimum extraction conditions were determined to be 60 mu L of 1-octyl-3-methyl imidazole six fluorine phosphate extraction solvent, 1000 mu L of acetonitrile as the dispersing solvent, vortex extraction time of 3 min, centrifugation for 5 min at room temperature at 10 000 rpm. After extraction, 30 mu L of extraction solvent was obtained from the sample for UHPLC analysis. It was shown that good linearity was obtained with butachlor and fipronil concentrations from 5 to 1000 mu g/kg with correlation coefficient of 0.999. The average recoveries were in the range of 90 to 104% at spiked levels from 10 to 50 mu g/kg with intra-day relative standard deviations lower than 3.7% (n = 6) and inter-day relative standard deviations lower than 6.1% (n = 3). The limits of detection were 0.5 and 0.3 mu g/kg for butachlor and fipronil, respectively.