同位素稀释高分辨气相色谱-高分辨质谱法测定土壤中痕量有机氯农药残留

Determination of trace organochlorine pesticides in soil using isotope dilution-high resolution gas chromatography-high resolution mass spectrometry

建立了同位素稀释高分辨气相色谱-高分辨质谱测定土壤中痕量有机氯农药残留的分析方法。采用加速溶剂法萃取土壤样品,以正己烷/丙酮(体积比为1∶1)为提取溶剂,提取液经过Florisil硅土固相萃取小柱净化后,采用高分辨DB-5MS毛细管色谱柱(30m×0.25mm×0.25μm)分离,以保留时间和同位素特征离子丰度比定性,同位素峰面积比定量。实验结果表明,方法的回收率为77.3%～114.5%,相对标准偏差(RSD)≤10.81%(n=5),检出限均小于0.04pg/g。应用该方法检测某地区表层土壤中的有机氯农药,结果表明该方法适合测定环境土壤背景中痕量有机氯残留。

A method for the determination of trace organochlorine pesticides （OCPs） in soil using isotope dilution and high resolution gas chromatography-high resolution mass spectrometry （ID-HRGC-HRMS） was developed. The sample was extracted by accelerated solvent extractor （ASE） and cleaned-up by a Florisil solid phase extraction （SPE） cartridge. The analytes were separated by HRGC on a DB-5MS column （30 m×0.25 mm×0.25 μm） and determined by HRMS. The identifications of OCPs were based on the retention time of ^13C-labelled standard and the abundance ratio of the two exact mass-to-charge ratios. The quantitative analysis was performed using the ratios of the integrated areas of the 13C-labelled standards. This method has the recoveries ranging from 77.3% to 114.5% and the relative standard deviations （RSD） less than 10.81% （n=5）. The limits of detection （LODs） of this method for all OCPs were lower than 0.04 pg/g. The results indicated that the method is rapid,selective and sensitive for precise determination requirements of organochlorine pesticides at trace level in soil.