加速溶剂萃取和净化-气相色谱-串联质谱法测定典型污染场地土壤中多氯联苯残留

Determination of Polychlorinated Biphenyls Residue in the Soils of Typical Polluted Area by Accelerated Solvent Extraction and Gas Chromatography Coupled with Triple Quadrupole Mass Spectrometry

建立了加速溶剂萃取同步净化-气相色谱-三重四极杆串联质谱法测定污染场地土壤中7种指示性多氯联苯的方法。对加速溶剂萃取、净化、色谱柱、串联质谱离子对、碰撞电压等条件进行了优化。萃取和净化过程合二为一,串联质谱法提高了7种多氯联苯的灵敏度。7种多氯联苯在0.1～100μg/L质量浓度范围内线性良好,线性相关系数为0.999 80～0.999 99,方法检出限为0.004～0.010μg/kg,回收率为84.8%～97.3%,相对标准偏差为2.4%～8.5%。运用网格法采集了华东某典型污染场地土壤中31个土壤样品,分析了该场地7种指示性多氯联苯的残留特征。7种多氯联苯的检出率为100%,检出范围为0.096～3 661μg/kg,各点平均值为307μg/kg。各采样点中多氯联苯的残留程度存在很大差异,局部点位受到了较重污染,与封存点相近的部分点位残留较外围位置高。土壤中多氯联苯同系物以三氯联苯、四氯联苯、五氯联苯为主,占同系物总量的98.2%。该污染场地土壤多氯联苯主要是低氯代联苯污染,土壤中多氯联苯的毒性效应评估处于中等水平,污染以点源污染为主,且已有较大程度扩散。

A method has been developed by using accelerated solvent extraction（ASE） and clean-up coupled with gas chromatography-triple quadrupole mass spectrometry（GC-QqQ/MS/MS） for simultaneous extraction,clean-up and determination of 7 indicator polychlorinated biphenyls in the soils of typical polluted area. The conditions of ASE, clean-up, chromatographic column, ion pairs（precursor ion/product ion）, collision voltage of triple quadrupole mass spectrometry were optimized. The process of extraction and clean-up was simultaneous. The detection sensitivity of 7 PCBs was improved markedly by triple quadrupole mass spectrometry. The linear correlation coefficients for 7 PCBs were 0.999 80-0.999 99 in the range of 0.1-100 μg/L. The limits of detection were 0.004-0.010 μg/kg. The recoveries range from 84.8% to 97.3% with the relative standard deviations（RSD） of 2.4%-8.5%. The residue characteristics of 7 indicator polychlorinated biphenyls were analysed in 31 soil samples collected in typical polluted area in east China region by using grid method. The detectable rate of 7 PCBs was 100%. The residues of 7 PCBs ranged from 0.096 to 3 661 μg/kg with the average of 307 μg/kg. There was a large difference in the residual degree of 7 PCBs in the different sampling points. The pollution was heavier in the local points and the residue of 7 PCBs near the mothballed points were higher than the peripheral ones. The trichloro biphenyl, tetrachlorobiphenyl and pentachloro biphenyl disturbance accounted for 98.2% of the PCBs in the soil, which indicated that the pollution of PCBs was low chlorinated biphenyl pollution in typical polluted area, the toxic effect of PCBs in the soil was in the middle level, and the pollution was mainly from the point source pollution with a large degree of diffusion.