SPE-GC-MS方法分析城市生活污水中多氯联苯的研究

要得到城市生活污水中多氯联苯的准确含量,必须选择合适的前处理方法.采用C18固相萃取柱富集生活污水中的PCBs,选择最佳用量为10 mL的组合萃取剂丙酮+正己烷(体积比为1∶1)进行萃取,结合浓硫酸洗涤、硅胶柱层析净化和无水硫酸钠干燥的方式深度提取PCBs;以EPA推荐的7种PCBs为外标物,采用GC-MS法对样品中的PCBs进行定性和定量分析.结果表明:城市生活污水中7种PCBs总量为27.75 ng/L.分析方法的相对标准偏差为1.6%~8.8%,回收率为84%~103%,检测限达到0.014μg/L.

Determinations of PCBs in Municipal Sewage with SPE-GC-MS

The optimum pretreatment process is especially required in order to get the exact concentration of PCBs in municipal sewage.In the paper,C18 solid-phase extraction(SPE) columns were adopted in the enriching of PCBs in Harbin municipal sewage,and the target compounds were extracted with mixed extractant of acetone and n-hexane of 1∶1 in the optimum dosage of 10 milliliter.And the extract was further purified with sulfuric acid,silica gel and anhydrous sodium sulfate.GC-MS was applied in the identification and quantification of PCBs in sewage samples,and seven PCBs congeners recommended by EPA were chosen as the exterior references.It indicated that the total concentration of the seven PCBs in the sewage samples was 27.75 ng/L,the relative standard deviations of the method were in the scope of 1.6%-8.8%,the recoveries were between 84% and 103%,and the lowest detection limit of PCBs was 0.014 μg/L.