气相色谱-质谱联用外标法检测4.5%高效氯氰菊酯中邻、间、对二甲苯的研究

目的建立气相色谱-质谱联用(GC/MC)检测4.5%高效氯氰菊酯(beta-cypermethrin)农药中邻二甲苯(ox)、间二甲苯(mx)、对二甲苯(px)的实验室方法,为含有二甲苯农药中毒的鉴定和诊治提供参考。方法选用外标标准曲线法对二甲苯三种同分异构体进行定量分析。优化的GC-MS色谱条件,达到二甲苯三种同分异构体完全分离,分别配制二甲苯ox、mx和px三种异构体的不同浓度梯度的标准溶液绘制标准曲线。标准样品及特征离子比对进行同分异构体定性,在选择离子模式下选用峰面积进行定量。结果二甲苯三种同分异构体在0.5~300 ng/ml之间线性均良好,线性相关系数(R2)均大于0.999。ox、mx和px的检出限(LOD)分别为0.48、0.46和0.42 ng/ml;定量限(LOQ)分别为1.61、1.54和1.40 ng/ml。方法的平均回收率大于94.2%,精密度相对标准偏差小于6.4%。结论 GC/MC外标标准曲线法用选择离子模式检测4.5%高效氯氰菊酯中二甲苯含量的方法灵敏性好、操作简便,可为农药中毒有机溶剂二甲苯成分法医学鉴定提供参考。

Analysis of o-xylene,m-xylene,p-xylene in 4.5 % beta-cypermethrin by gas chromatography/mass spectrometry using external standard method

Objective The aim of this study is to develop the external standard method for analysis of o-xylene, m-xylene, p-xylene in 4.5% beta-cypermethrin by GC/MS. This method could be applied as a reference for forensic identification and treatment of xylene-poisoning. Methods Chromatographic conditions have been established in order to obtain a good separation of three xylene isomers. Standard curves for o-xylene, m-xylene, and p-xylene were constructed. Comparisons of standard and characteristic ion were performed for identifying xylene isomers, and the positive single-ion monitoring （SIM） mode was used for quantification. Results The target compounds could be detected within a linear dynamic range of 0.5-300 ng/mL by a linear determination coefficient （R2） greater than 0.999. The limit of detection （LOD） of ox, mx and px isomers of xylene were 0.48, 0.46 and 0.42 ng/ml, respectively, and the limit of quantification （LOQ） were 1.61, 1.54 and 1.40 ng/ml. The method achieved a good accuracy （Average Recovery〉94.2% ） and precision （RSD 〈6.4% ）. Conclusion This established GC/MS quantification method with external standard curves was utilizing single-ion monitoring （SIM） positive mode. It is a highly sensitive, versatile and flexible technique for monitoring and analyzing three isomers of xylene in 4.5 % beta- cypermethrin. And it could be used as a reference for forensic identification and treatment of poisoning with xylene.