气相色谱-串联质谱法测定西瓜和黄瓜中吡唑萘菌胺及其代谢物残留

基于分散固相萃取与气相色谱-串联质谱建立了快速检测西瓜和黄瓜中吡唑萘菌胺及其代谢物残留的分析方法。样品经乙腈提取，N-丙基乙二胺 (PSA) 和C₁₈净化，气相色谱-串联质谱 (GC-MS/MS) 测定，多反应检测模式 (MRM) 分析，内标法定量。考察了提取溶剂及吸附剂种类对分析结果的影响，优化了气相色谱-质谱条件。结果表明:在1~500 μg/L范围内，吡唑萘菌胺及其代谢物的质量浓度与对应的峰面积间均呈良好的线性关系，相关系数 (r) 为0.994 3~0.999 9。在0.01、0.1和1 mg/kg 3个添加水平下，吡唑萘菌胺及其代谢物在西瓜中的平均回收率为70%~105%，相对标准偏差 (RSD，n = 5) 为3.4%~13%；在黄瓜中的添加回收率为82%~104%，相对标准偏差 (RSD，n = 5) 为1.3%~9.3%。吡唑萘菌胺及其代谢物的定量限 (LOQ，S/N = 10) 为0.3~0.6 μg/kg，检出限 (LOD，S/N = 3) 为0.1~0.2 ng。该方法简单、高效、快速，满足残留分析的要求，适用于西瓜、黄瓜中吡唑萘菌胺及其代谢物残留的快速检测。

Determination of isopyrazam and its metabolites residues in watermelon and cucumber by gas chromatography-tandem mass spectrometry

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method for the determination of isopyrazam and its metabolites residues in watermelon and cucumber was developed using dispersive solid-phase extraction as the sample preparation method. The samples were extracted with acetonitrile, purified with primary secondary amine and C₁₈ purificant, determined using GC-MS/MS, analyzed under multiple reaction monitoring (MRM) mode, and quantified by internal standard method. Factors influencing the extraction efficiency, such as the type of extraction solvent, clean-up sorbent and instrumental condition, were optimized. The results indicated that the calibration curves were linear in the range of 1-500 μg/L and the correlation coefficient of 0.994 3-0.999 9 for isopyrazam and its metabolites. In terms of watermelon samples, the recoveries at spiked levels of 0.01, 0.1 and 1 mg/kg were 70%-105%, with the relative standard deviations (RSD, n = 5) of 3.4%-13%. With regard of cucumber samples, and the recoveries at the same spiked levels were 82%-104%, with the relative standard deviations (RSD, n = 5) of 1.3-9.3%. The limits of quantity (S/N = 10) for the isopyrazam and its metabolites were 0.3-0.6 μg/kg and the limits of detection (S/N = 3) were 0.1-0.2 ng. This developed method is easy, quick and efficiency.