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    加速溶剂萃取分离-气相色谱-质谱法测定土壤中多溴二苯醚和六溴联苯的含量

    Determination of Polybromo Diphenyl Ethers and Hexabromobiphenyl in Soil by Gas Chromatography-Mass Spectrometry with Separation by Accelerated Solvent Extraction

    • 摘要: 称取经风干和剔除砂、石等杂质并研磨通过0.18 mm孔径筛的土壤样品2.000 g与2.0 g硅藻土混合,加入2 000 μg·L-1同位素内标溶液(MBDE-MXFS) 50 μL和5 000 μg·L-1 13C12-BDE-209标准溶液40 μL,用正己烷-二氯甲烷(1+1)混合液进行加速溶剂萃取(ASE)。将所得萃取液浓缩至1~2 mL,通过多层复合酸碱硅胶层析柱净化,用正己烷100 mL洗脱,收集洗脱液,使其浓缩至1~2 mL,再经氮吹浓缩至0.1 mL,加入2 000 μg·L-1 13C12-BDE-138进样内标溶液50 μL,定容至1.0 mL,进样进行气相色谱-质谱分析。测定三溴至七溴代二苯醚(BDEs)和六溴联苯(BB-153)时,按气相色谱-电子轰击离子源-低分辨质谱工作条件并选用Rtx-1614色谱柱(30 m×250 μm,0.10 μm);测定BDE-209时,按气相色谱-负化学电离源-低分辨质谱工作条件并选用Rtx-1614色谱柱(15 m×250 μm,0.10 μm)。测得BDE-209的线性范围为50.0~1 000 μg·L-1,其余7种PBDEs和BB-153的线性范围均为5.00~500 μg·L-1;检出限(3s)在0.04~0.51 μg·L-1。用标准加入法进行回收试验,测得回收率为82.6%~112%;测定值的相对标准偏差(n=5)为1.8%~8.6%。

       

      Abstract: After air-drying and rejecting mixed sand and stone, the soil was gound to pass the sieve with mesh-diameter of 0.18 mm. A portion (2.000 g) of the soil sample was mixed homogeneously with 2.0 g of diatomite, and to this sample mixture, 50 μL of the isotopic internal standard solution (2 000 μg·L-1 MBDE-MXFS) and 40 μL of 5 000 μg·L-1 13C12-BDE-209 standard solution were added and this mixture was extracted by accelerated solvent extraction (ASE) with mixed solvent of n-hexane and dichloromethane (1+1). The extract obtained was evaporated to 1-2 mL, and purified by passing through multilayer silica gel column. Analytes on the column were then eluted with 100 mL of n-hexane, and the eluate was collected and evaporated to 1-2 mL and further concentrated to 0.1 mL by N2-blowing. Then 50 μL of sample introducing internal standard solution of 2 000 μg·L-1 13C12-BDE-138 were added and its total volume was made up to 1.0 mL, which was used for GC-MS analysis. For determination of trilbrono- to hepta-bromo diphenyl ethers (PBDEs) and hexabromobiphenyl (BB-153), instrumental conditions of GC-EI/LRMS and chromatographic column of Rtx-1614 (30 m×250 μm, 0.10 μm) were used, while for determination of BDE-209, the instrumental conditions of GC-NCI/LRMS and the column of Rtx-1614 (15 m×250 μm, 0.10 μm) were used. Linearity range found for BDE-209 was 50.0-1 000 μg·L-1, and those for the remainder 7 PBDEs and BB-153 were found same 5.00-500 μg·L-1. Values of detection limits (3s) found ranged from 0.04 to 0.51 μg·L-1. Recovery was tested by standard addition method, and values of recovery found were in the range of 82.6%-112%. RSDs (n=5) found ranged from 1.8% to 8.6%.

       

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