固相萃取-气相色谱-质谱联用法测定蔬菜中烯肟菌胺的残留及其裂解机理

建立了蔬菜中烯肟菌胺残留量的固相萃取-气相色谱-质谱联用（SPE-GC-MS）分析方法；对烯肟菌胺的裂解机理进行了探讨；确定了测试分析的定性离子和定量离子。样品采用乙酸乙酯高速分散提取，以无水硫酸镁、硅胶和石墨化炭黑（GCB）为混合填料进行固相萃取净化，气相色谱-质谱联用仪在选择离子扫描（SIM）模式下进行检测，基质匹配标准溶液外标法定量。结果显示:烯肟菌胺在0.02~1 mg/L内，标准溶液的峰面积与质量浓度呈良好的线性关系（r>0.999）；在0.02~0.2 mg/kg添加水平下，烯肟菌胺的平均回收率为94%~99%，相对标准偏差（RSD，n=6）为2.3%~2.9%；方法的检出限（LOD）（S/N=3）为0.006 mg/kg，定量限（LOQ）（S/N=10）为0.02 mg/kg。

Determination of fenaminstrobin in vegetables by gas chromatography-mass spectrometry with solid phase extraction and its fragmentation mechanism

A solid phase extraction coupled with gas chromatography-mass spectrometric(SPE-GC-MS) method was established for the determination of fenaminstrobin(SYP-1620) residue in vegetables.The target analytes in samples were extracted with ethyl acetate in high-speed homogenate extraction,followed by solid phase extraction clean-up with the mixture of anhydrous magnesium sulphate(MgSO₄),silicone gel and graphitized carbon(GCB),analyzed by GC-MS under selected ion monitor mode(SIM) and quantified by matrix-match standard solution in external standard method.Good linear was obtained in the range of 0.02-1.00 mg/L for fenaminstrobin with correlation coefficient not less than 0.999 under the optimum conditions,and the limits of detection(S/N=3) and the limits of quantitation(S/N=10) were 0.006 mg/kg and 0.02 mg/kg,respectively.The average recoveries of fenaminstrobin from blank samples at three spiked levels of 0.02,0.04 and 0.2 mg/kg ranged from 94% to 99% with RSDs of 2.3%-2.9%.The fragmentation mechanism of fenaminstrobin was also studied in this article in which the qualitative ions and quantitative ions were confirmed.