气相色谱/高分辨质谱联用测定环境样品中的二噁英和类二噁英多氯联苯

Determination of 2,3,7,8-Substituted Polychlorinated Dibenzo-p-dioxins-Dibenzofurans and Dioxin-like Polychlorinated biphenyls in Environmental Samples by Gas Chromatography/High Resolution Mass Spectrometry

样品采用索氏抽提,抽提液依次经酸性硅胶床、多段混合硅胶柱和凝胶渗透色谱柱(GPC)净化后,用Florisil硅藻土柱分离出样品中的二噁英(PCDD/Fs)和类二噁英多氯联苯(dioxin-like PCBs),采用同位素稀释法和气相色谱/高分辨质谱联用仪(GC/HRMS)测定了其中的17个2,3,7,8-氯取代二噁英类化合物和12个类二噁英多氯联苯。结果表明,用该法分析二噁英和多氯联苯标准溶液,平行4次的分析结果为:RSD(PCDD/Fs)<8.9%,RSD(PCBs)<11.4%;回收率可达60%-105%。PCDD/Fs和PCBs的检出限分别为0.1-0.8 pg/g和0.05-0.6 pg/g。应用本方法成功测定了沉积物、淤泥、土壤和飞灰中的二噁英和类二噁英多氯联苯,并计算出它们的毒性当量。

A method was evaluated for the determination of seventeen 2,3,7,8-substitituted polychlorinated dibenzo-p-dioxins and dibenzofurans （ PCDD/Fs ） and 12 dioxin-like polychlorinated biphenyls （ PCBs ） in environmental samples with isotope dilution-gas chromatography/high resolution mass spectrometry. Sample extracts were cleaned up successively with acid silica gel slurry, multi-layer silica gel column and gel permeation chromatography column. Florisil column was used to separate PCBs from PCDD/Fs. Precise and recoveries of the entire procedure were evaluated by replicate analysis （ n = 4） of PCDD/Fs and PCBs standard solutions, with RSD below 8.9% and 11.4% for PCDD/Fs and PCBs, respectively, and with the recoveries in the range of 60% -105%. The detection limits of PCDD/Fs and dioxin-like PCBs were 0.1 -0.8 pg/g and 0.05 -0.6 pg/g respectively. PCDD/Fs and dioxin-like PCBs were successfully determined in environmental samples such as sediment, slurry, soil and fly ash, and then their toxic equivalent was calculated.