气相色谱-负化学电离源-质谱技术检测毒莠定中的六氯苯残留

Determination of Hexachlorobenzene Pesticide Residues in Picloram by Capillary Gas Chromatography-Negative Chemical Ionization Mass Spectrometry Analysis

采用气相色谱-负化学电离源-质谱（GC-NCI-MS）技术对出口农药毒莠定中的六氯苯（HCB）残留进行检测，获得比气相色谱-电子电离源-质谱（GC-EI-MS）技术高2个数量级的检测灵敏度。实验中重点对离子源温度和反应气流速进行了研究。使用选择性扫描（SIM）检测时，在离子源温度为100℃、反应气流速为2．5mL/min的条件下，方法的检测限可达0．012μg／L，定量下限为1μg/L，相关系数的平方（R^2）为0．9991。检测发现，毒莠定样品中六氯苯含量均在0．727～1．527μg/g之间，样品加标回收率在81．2％～113．8％之间。

The capillary gas chromatography-negative chemical ionization mass spectrometry （GC-NCI-MS） tech- nique has been applied for the determination of hexachlorobenzene（HCB） pesticide residues in picloram samples. The sensitivity gained by GC-NCI-MS is 100 times higher than that gained by the capillary gas chromatography-electron ionization mass spectrometry（GC-EI-MS）. The parameters of negative chemical ionization mass spectrometry, such as ion source temperature, the flow of reaction gas are emphatically studied. Ion source temperature of 100℃ and the flow of reaction gas of 2.5mL/min are the suitable technical parameters. When selected-ions monitoring（ m/z） are 283,285and 287 ,detection limit of 0. 012μg/L,lower limit quantify of 1μg/L,and square of correlation coefficient（R^2） of 0.9991 are obtained using GC-NCI-MS. In picloram samples,the contents between 0. 727 and 1. 527μg/g are detected. The recoveries were in the range of 81.2% -113.8%.