Simultaneous Measurement of Free and Total Concentrations of Hydrophobic Compounds
Simultaneous Measurement of Free and Total Concentrations of Hydrophobic Compounds
复制标题
DOI：
10.1021/es8037033
复制
发表时间：
2009-05-15
影响因子：
11.4
通讯作者：
Gan, Jay
中科院分区：
文献类型：
--
作者：
Bondarenko, Svetlana;Gan, Jay
疏水性污染物在水和吸附剂相之间分配，例如环境基质中的溶解有机物（DOM）。考虑生物利用度越来越需要测量自由溶解的浓度（C-free），除了总的化学浓度（C-total）。然而，目前的做法需要使用单独的方法和样品来获得游离碳和总碳，并且没有方法可以同时测量两种浓度。我们采用固相微萃取（SPME）与同位素标记的内标物和气相色谱-质谱（GC-MS）联用的方法进行检测。以8种拟除虫菊酯为模型化合物，C-13-顺式二氯苯醚菊酯为标记内标，建立了该方法。分析4加标沉积物孔隙水和4场污染的样品表明，通过这种方法获得的总碳浓度与加标浓度或全样品溶剂提取后测得的总浓度接近一致，而无碳只是总碳的一小部分，这表明这些化合物与DOM的显着关联。方法重现性好，平均相对标准偏差
Hydrophobic contaminants partition between water and sorbent phases such as dissolved organic matter (DOM) in environmental matrices. Consideration of bioavailability increasingly requires the measurement of freely dissolved concentration (C-free) in addition to the total chemical concentration (C-total). However, current practices require the use of separate methods and samples to derive C-free and C-total, and no method affords simultaneous measurement of both concentrations. We employed a method by coupling solid-phase microextraction (SPME) with the use of an isotope-labeled internal standard and gas chromatography-mass spectrometer (GC-MS) for detection. The method was demonstrated using 8 pyrethroids as model compounds and C-13-cis-permethrin as the labeled internal standard. Analysis of 4 spiked sediment porewater and ;4 field-contaminated samples showed that C-total obtained by this method was in close agreement with the spiked concentrations or the total concentrations measured after whole-sample solvent extraction, while C-free was only a small fraction of C-total, suggesting pronounced association of these compounds with DOM. The method displayed good reproducibility with average relative standard deviation