蔬菜中杀扑磷农药残留的气相色谱-串联质谱法测定的新方法研究

New Method for Determination of Methidathion Residues in Vegetables by Gas Chromatography-Tandem Mass Spectrometry

为准确测定蔬菜中的杀扑磷残留,建立了气相色谱-串联质谱测定蔬菜中杀扑磷农药残留的分析方法。具体方法为:用乙腈提取蔬菜中的杀扑磷,经石墨炭黑氨基固相萃取小柱净化,再用丙酮定容,用外标法定量,以气相色谱-串联质谱(GC-MS/MS)测定。结果表明:样品中加入0.02～0.40 mg/kg质量分数水平的杀扑磷,回收率在92.2%～109.3%之间,RSD在1.1%～7.3%范围内,在0.02～1.00 mg/kg的范围内具有良好的线性关系,相关系数为0.992 6,检出限为0.001 8 mg/kg。这表明该分析方法具有高灵敏度、有效排除基质干扰、定性准确的特点。

In order to determine the methidathion residues in vegetables accurately, a method by using gas chromatography-tandem mass spectrometry （GC-MS/MS） was established. The methidathion residues in vegetables were extracted by using acetonitrile, then were purified by the carbon/NH2 SPE column, then were diluted with acetone, and then were determined by GC-MS/MS under MRM mode which using the external standard method. The results showed that when adding 0.02-0.40 mg/kg of methidathion to the sample, the recovery rate ranged from 92.2% to 109.3% with RSD of 1.1%-7.3%; there were good linear relationship when concentration of methidathion ranged from 0.02 mg/kg to 1.00 mg/kg, the correlation coefficient was 0.992 6 and the detection limits was 0.001 8 mg/kg. Therefore, it proved the method is sensitive and accurate, which can exclude the possibility of interference effectively.