Simultaneous determination and dissipation behaviour of thifluzamide and difenoconazole in grapes using a QuEChERS method with ultra high-performance liquid chromatography and tandem mass spectrometry

摘要

In this study, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for the simultaneous determination of thifluzamide and difenoconazole in grapes by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) using a Waters Acquity UHPLC BEH C18 column. To compare the effects of different sorbents for thifluzamide and difenoconazole in grapes, samples were extracted with acetonitrile and cleaned up using five different types of sorbents at the same concentration level (0.1 mg/kg). The method was validated at three fortification concentrations (0.05, 0.1, 0.5 mg/kg) with five replicates in each matrix using 40 mg of primary secondary amine (PSA) + 10 mg of graphitised carbon black (GCB) as clean-up sorbents. The recoveries were between 76.3 and 109.3%, and the RSDr (intra-day precision, n = 5) and RSDR (inter-day precision, n = 15) values ranged from 3.5 to 8.1% and 5.8 to 22.2%, respectively. The limits of quantification (LOQ) for thifluzamide and difenoconazole were 0.07 and 0.04 mg/kg, respectively. The method showed excellent linearity and reliability. The results demonstrated that the method was effective in detecting the two compounds. In this study, we also investigated the dissipation behaviours of thifluzamide and difenoconazole in grapes. The dissipations of thifluzamide and difenoconazole followed the first-order kinetics with the half-lives of 3.9-16.3 days.