Determinationof6pesticidesresiduesin<italic>Fritillariathunbergii</italic>byultraperformanceliquidchromatography-tandemmassspectrometry

A method for the simultaneous determination of imidacloprid, pyrisoxazole, fluxapyroxad, cyprodinil, pyraclostrobin, abamectin in Fritillaria thunbergii Miq. was developed using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). F. thunbergii samples were extracted by V(acetonitrile): V(water)=4 : 1. Then they were cleaned up by PSA 50 mg + C₁₈ 50 mg + MgSO₄150 mg adsorbents and detected by UPLC-MS/MS under positive polarity multiple reactions monitoring (MRM) mode. The matrix-matched external standard calibration curves were used for quantitative analysis. The linearities of 6 pesticides were all in the range of 0.001-0.2 mg/L, with correlation coefficients higher than 0.994. The limit of quantification (LOQ) was 0.01 mg/kg and the limits of detection (LOD) of this new method were 2×10^–5 mg/kg to 3 ×10^–4 mg/kg in fresh F. thunbergii. While the LOQ was 0.05 mg/kg and the LOD of the proposed method were 1×10^–4 mg/kg to 1×10^–3 mg/kg in dry F. thunbergii. Recoveries at three spiked levels of 0.01, 0.5 and 2 mg/kg ranged from 80% to 109% with relative standard deviations (RSDs) from 0.95% to 13% (n=5) in fresh F. thunbergii. While, in dry F. thunbergii, recoveries at three spiked levels of 0.05, 0.5 and 2 mg/kg ranged from 77% to 101% with RSDs from 0.89% to 7.5% (n=5). The application of this new method in real samples has been demonstrated. Given that this method is fast, simple, accurate and efficient, it can meet the requirements for the determination of residues of imidacloprid, pyrisoxazole, fluxapyroxad, cyprodinil, pyraclostrobine, abamectin in F. thunbergii.