Simultaneous Determination of Tebufenozide and Phoxim in Chinese Cabbage and Soil Using Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry

This study demonstrates a new, rapid, and sensitive analytical method for the simultaneous determination of tebufenozide and phoxim in cabbage and soil using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation procedure followed by ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry. Tebufenozide and phoxim were extracted with acetonitrile and subsequently cleaned up with a primary and secondary amine sorbent prior to sample analysis. Recoveries ranged from 77.2 to 107.3 % for all analytes, with relative standard deviation values lower than 8.8 % in matrices at three levels (0.005, 0.01, 0.1 mg/kg). The limit of quantification for tebufenozide and phoxim in cabbages and soil was 0.005 mg/kg, respectively. The developed method was used to study the dissipation of the pesticides in cabbage and soil in a field trial. The tebufenozide and phoxim dissipated with half-life of 4.5–4.8 and 0.7–0.7 days (in cabbage) and 10.8–12.7 and 1.1–1.5 days (in soil), respectively. The final residue concentrations of tebufenozide and phoxim were 0.022–0.482 and 0.029–0.042 mg/kg (in cabbage) and 0.029–0.487 and 0.025–0.043 mg/kg (in soil), respectively. The results further confirmed the reliability and efficacy of the proposed method for routine pesticide residue monitoring in soil and cabbage samples.