气相色谱-质谱/质谱法检测蔬菜中的毒死蜱及其代谢物

建立了蔬菜中毒死蜱及其代谢物3，5，6-三氯-2-羟基吡啶（3,5,6-trichloro-2-pyridinol，TCP)的气相色谱-质谱/质谱分析方法。蔬菜样品采用丙酮提取,浓缩后TCP用N-甲基-N-叔丁基二甲基硅基三氟乙酰胺(MTBSTFA)衍生,再经氟罗里硅土固相萃取柱净化。采用三重四极杆质谱电子轰击多反应监测(MRM)模式测定。采用内标法对毒死蜱定量,方法的检出限为1 μg/kg，加标回收率为75.57%～106.41%,相对标准偏差(RSD)为8.33%～17.58%。采用外标法对TCP定量,方法的检出限为0.5 μg/kg,加标回收率为69.11%～108.43%,RSD为5.20%～19.42%。在2～100 μg/L范围内,两种被测物的线性关系良好（r＞0.99）。该方法可用于蔬菜中毒死蜱及其代谢物的检测。

Determination of chlorpyrifos and its metabolite in vegetables using gas chromatography-tandem mass spectrometry

A method was developed for the determination of chlorpyrifos and its metabolite3,5,6-trichloro-2-pyridinol (TCP) in vegetables using gas chromatography-tandem mass spectrometry （GC-MS/MS）. The sample was extracted with acetone. After the concentration, TCP was derivatized with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA). The purification was performed using a florisil solid-phase extraction cartridge. The analyte was detected by triple quadrupole MS in multi-reaction monitoring mode. An internal standard method was used for the quantification of chlorpyrifos, the limit of quantification was 1 μg/kg, and the recoveries were in the range of 75.57%-106.41% with the relative standard deviations (RSDs) of 8.33%-17.58%. An external standard method was used for the quantification of TCP, the limit of quantification was 0.5 μg/kg, and the recoveries were in the range of 69.11%-108.43% with the RSDs of 5.20%-19.42%. The good linear relationships were obtained in the range of 2-100 μg/L for the both target analytes. The method can be applied for the determination of chlorpyrifos and its metabolite in vegetables.