Department of Biology, University of Eastern Finland, P.O. Box 111, FIN-80101 Joensuu, Finland.
Environ Sci Technol. 2011 Feb 1;45(3):1041-7. doi: 10.1021/es1029969. Epub 2010 Dec 21.
The equilibrium sampling in silicone is increasingly applied to measure freely dissolved concentrations and chemical activities within bioaccumulation research of hydrophobic organic chemicals. Two equilibrium methods were applied to PCB-contaminated soil and sediment, and directly calibrated with respect to equilibrium partitioning concentrations in lipids (C(lipid,partitioning)): (i) Solid phase microextraction in the headspace above the sample (HS-SPME) required optimization for its application to PCBs, and it was calibrated above external partitioning standards in olive oil. (ii) Equilibrium sampling with internally coated glass jars with varying thicknesses of silicone (PDMS) resulted in proportionality between coating and analyte mass, which confirmed several validity criteria. C(lipid,partitioning) was here determined as product of PDMS concentration and PDMS to lipid partition ratio. The results of the two methods were in good agreement and thus validated each other. Finally, the coated glass jar method was applied to field sediment containing invertebrates, which lead to C(lipid,partitioning) that were about two times higher than measured lipid-normalized concentrations in the organisms. Temperature differences and animal lipid structure were discussed as possible reasons for this discrepancy. Both methods combine high analytical performance, reduced equilibration times and new calibration possibilities, which makes them suited for bioaccumulation research and environmental monitoring.
平衡采样在硅橡胶中的应用越来越广泛，可用于测量生物蓄积研究中疏水性有机化学物质的游离溶解浓度和化学活性。本研究采用两种平衡方法对 PCB 污染土壤和沉积物进行了研究，并用脂质平衡分配浓度（C（lipid，partitioning））直接进行了校准：（i）直接应用于 PCB 的顶空固相微萃取（HS-SPME）需要进行优化，并在橄榄油中用外部分配标准进行校准。（ii）用不同厚度的聚二甲基硅氧烷（PDMS）对内涂玻璃罐进行平衡采样，涂层和分析物质量之间呈比例关系，这证实了几个有效性标准。C（lipid，partitioning）为 PDMS 浓度与 PDMS 与脂质分配比的乘积。两种方法的结果非常吻合，因此相互验证。最后，该涂覆玻璃罐方法应用于含有无脊椎动物的现场沉积物，得到的 C（lipid，partitioning）比生物体中测量的脂质归一化浓度高约两倍。讨论了温度差异和动物脂质结构可能是造成这种差异的原因。这两种方法均具有高分析性能、缩短平衡时间和新的校准可能性，非常适合生物蓄积研究和环境监测。
