Ripszam Matyas, Haglund Peter
Department of Chemistry, Ume, å, University, Umeå, Sweden.
Environ Toxicol Chem. 2015 Feb;34(2):266-74. doi: 10.1002/etc.2805. Epub 2015 Jan 8.
Dissolved organic carbon (DOC) plays a key role in determining the environmental fate of semivolatile organic environmental contaminants. The goal of the present study was to develop a method using commercially available hardware to rapidly characterize the sorption properties of DOC in water samples. The resulting method uses negligible-depletion direct immersion solid-phase microextraction (SPME) and gas chromatography-mass spectrometry. Its performance was evaluated using Nordic reference fulvic acid and 40 priority environmental contaminants that cover a wide range of physicochemical properties. Two SPME fibers had to be used to cope with the span of properties, 1 coated with polydimethylsiloxane and 1 coated with polystyrene divinylbenzene polydimethylsiloxane, for nonpolar and semipolar contaminants, respectively. The measured DOC-water distribution constants showed reasonably good reproducibility (standard deviation ≤ 0.32) and good correlation (R(2) = 0.80) with log octanol-water partition coefficients for nonpolar persistent organic pollutants. The sample pretreatment is limited to filtration, and the method is easy to adjust to different DOC concentrations. These experiments also utilized the latest SPME automation that largely decreases total cycle time (to 20 min or shorter) and increases sample throughput, which is advantageous in cases when many samples of DOC must be characterized or when the determinations must be performed quickly, for example, to avoid precipitation, aggregation, and other changes of DOC structure and properties. The data generated by this method are valuable as a basis for transport and fate modeling studies.
溶解有机碳(DOC)在决定半挥发性有机环境污染物的环境归宿方面起着关键作用。本研究的目的是开发一种使用市售硬件快速表征水样中DOC吸附特性的方法。所得方法采用可忽略损耗的直接浸入式固相微萃取(SPME)和气相色谱 - 质谱联用技术。使用北欧参考富里酸和40种涵盖广泛物理化学性质的优先环境污染物对其性能进行了评估。由于性质跨度的原因,必须使用两根SPME纤维,一根涂有聚二甲基硅氧烷,另一根涂有聚苯乙烯二乙烯基苯聚二甲基硅氧烷,分别用于非极性和半极性污染物。对于非极性持久性有机污染物,测得的DOC - 水分配常数显示出相当好的重现性(标准偏差≤0.32)和良好的相关性(R² = 0.80)与正辛醇 - 水分配系数。样品预处理仅限于过滤,并且该方法易于调整以适应不同的DOC浓度。这些实验还采用了最新的SPME自动化技术,该技术大大缩短了总循环时间(至20分钟或更短)并提高了样品通量,这在必须表征许多DOC样品或必须快速进行测定的情况下具有优势,例如,以避免DOC结构和性质的沉淀、聚集及其他变化。该方法生成的数据作为迁移和归宿模型研究的基础很有价值。