液相色谱-串联质谱法同时测定菠菜、土壤及水体中螺虫乙酯及4种代谢物残留

采用QuEChERS及固相萃取样品前处理方法，结合液相色谱-三重四极杆串联质谱技术（LC-MS/MS），以负离子扫描和多反应监测模式（MRM），建立了菠菜、土壤及水体中螺虫乙酯及4种代谢物（B-enol、B-keto、B-mono和B-glu）残留的检测方法。通过对质谱检测条件的优化表明，以乙腈-0.5%甲酸水溶液作为流动相，采用梯度洗脱时，色谱分离度及灵敏度最好。通过对样品前处理条件的考察，发现选用0.1%甲酸-乙腈溶液作为提取溶剂，经50 mg的m（PSA）:m（GCB）=1:1净化处理后，在0.05、0.5和1 mg/kg添加水平下，螺虫乙酯及4种代谢物在菠菜中的回收率为81%~103%，相对标准偏差（RSD）为1.7%~7.9%；在土壤样品中的回收率为82%~98%，RSD为1.9%~7.6%。采用NH2柱作为固相萃取柱，用10 mL二氯甲烷洗脱，在0.005、0.05和0.5 mg/L添加水平下，螺虫乙酯及4种代谢物在水体中的回收率为82%~95%，RSD为1.5%~6.2%。在0.002~1 mg/L范围内，螺虫乙酯及4种代谢物的质量浓度与对应的峰面积间呈现良好的线性关系，r在0.996 7~0.999 7之间。检出限（S/N=3）分别为螺虫乙酯（0.000 2~0.000 3 mg/kg），B-enol（0.000 1~0.000 3 mg/kg），B-keto（0.000 4~0.000 6 mg/kg），B-mono（0.000 4~0.000 7 mg/kg），B-glu（0.000 2~0.000 6 mg/kg）；定量限（S/N=10）分别为螺虫乙酯（0.000 6~0.001 mg/kg），B-enol（0.000 3~0.001 mg/kg），B-keto（0.001 2~0.001 6 mg/kg），B-mono（0.001 2~0.001 9 mg/kg），B-glu（0.000 6~0.001 3 mg/kg）。方法分析结果符合农药残留检测要求，适用于菠菜、土壤及水体中螺虫乙酯及4种代谢物残留的同时检测。

Simultaneous determination of spirotetramat and its four metabolites in Spinacia oleracea L., soil and water using liquid chromatography-tandem mass spectrometry

A rapid and sensitive method based on QuEChERS and solid phase extraction using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative ion scanning and multiple reaction monitoring (MRM) mode was developed for the residue detection of spirotetramat and its four metabolites (B-enol, B-keto, B-mono and B-glu) in Spinacia oleracea L., soil and water. When using aqueous phase of acetonitrile-0.5% formic acid as the mobile phase, gradient elution resulted in the best chromatographic resolution and sensitivity. When 0.1% formic acid-acetonitrile solution was used as the extraction solvent and the samples was purified by 50 mg m (PSA): m (GCB) = 1: 1, at the fortification levels of 0.05, 0.5 and 1mg/kg, the recoveries of spirotetramat and its four metabolites in spinach and soil were 81%-103% and 82%-98%, the RSD were 1.7%-7.9% and 1.9%-7.6%, respectively. The recoveries of spirotetramat and its four metabolites in water was 82%-95%, the RSD was 1.5%-6.2%, at the fortification levels of 0.005, 0.05 and 0.5 mg/L when the NH₂ column was used as the solid phase extraction column and 10 mL of dichloromethane was used as the elution solvent. At concentrations ranging from 0.002-1 mg/L, there were good linear relationships between the mass concentration of spirotetramat and its four metabolites and the corresponding peak area, the correlation coefficients (r) were in the range 0.996 7-0.999 7. The limits of detection (S/N = 3) for all analytes were 0.000 2-0.000 3 mg/kg (spirotetramat), 0.000 1-0.000 3 mg/kg (B-enol), 0.000 4-0.000 6 mg/kg (B-keto), 0.000 4-0.000 7 mg/kg (B-mono), 0.000 2-0.000 6 mg/kg (B-glu), respectively. The limits of quantification (S/N = 10) for all analytes were 0.000 6-0.001 mg/kg (spirotetramat), 0.000 3-0.001 mg/kg (B-enol), 0.001 2-0.001 6 mg/kg (B-keto), 0.001 2-0.001 9 mg/kg (B-mono), 0.000 6-0.001 3 mg/kg (B-glu), respectively. The method analysis results met the requirements for pesticide residue analysis. And this method is applicable to simultaneous detection of spirotetramat and its four metabolites in spinach, soil and water.