高分辨气相色谱/高分辨质谱联用测定大气降尘中的二噁英

Determination of Dioxins in Atmospheric Deposition by High Resolution Gas Chromatography/High Resolution Mass Spectrometry

样品采取索氏抽提，抽提液依次经多段混合硅胶柱、氧化铝柱和硅胶柱净化后，采用同位紊稀释法和高分辨气相色谱／高分辨质谱联用仪（HRGC／HRMS）对其中的17个2，3，7，8-氯取代二噁英（PCDD／Fs）同系物进行了测定。研究结果表明，用本法4次分析二噁英标准溶液，其结果的RSD〈7．1％；回收率可达62％～103％；标准参考样品的分析结果与标准值基本吻合，3次实验结果的RSD≤15％；仪器检出限为2，3，7，8-TCDF0．1pg,2,3，7，8-TCDD 0．2pg，OCDD 0．8Pg；测定某降尘样品中二噁英，计算得降尘通量为14．02pg TEQm^-1day^-1。

A method was evaluated for the determination of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） in atmospheric deposition with isotope dilution-high resolution gas chromatography/high resolution mass spectrometry （HRGC/HRMS）. Sample extracts were cleaned up successively through multi-layer silica gel, alumina and silica gel columns. Precise and recoveries of the entire procedure were evaluated by replicate analysis （n =4） of PCDD/Fs standard solutions, with RSD below 7.1% and the recoveries in the range of 62% - 103%. The method was also validated by replicate analysis （ n = 3） of certified reference material. The values determined were in agreement with those certified, and the RSD below 15%. The detection limits were o. 1 pg for 2,3,7,8-tetrachlorodibenzofuran, 0. 2 pg for 2,3,7,8- tetrachlorodibenzo-p-dioxin and 0. 8 pg for octachlorodibenzo-p-dioxin. PCDD/Fs were analyzed in an atmospheric deposition sample, with the deposition flux of 14.02 pg m-2 day-l toxicity equivalent.