Department of Chemistry, Natural Sciences Complex, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States.
Environ Sci Technol. 2011 Apr 1;45(7):2917-24. doi: 10.1021/es1031097. Epub 2011 Mar 7.
The increasing production and use of quantum dot (QD) nanoparticles have caused concerns on the possibility of contaminating the aquatic and terrestrial ecosystems with wastes that may contain QDs. Therefore, studies on the behavior of QDs upon interaction with components of the natural environment have become of interest. This study investigated the fluorescence and electrophoretic mobility of carboxylic or amine polyethylene glycol (PEG)-functionalized CdSe/ZnS QDs in the presence of two aquatic humic substances (HS), Suwannee River humic and fulvic acids, using capillary electrophoresis with laser-induced fluorescence detection. Results showed initial enhancement in fluorescence of QDs at the onset of the interaction with HS, followed by fluorescence quenching at longer exposure with HS (>30 min). It was also observed that the electrophoretic mobility of QDs increases with increasing concentration of HS, suggesting an increase in the ratio in charge to hydrodynamic size of the nanoparticles. To determine if the QDs degraded upon interaction with HS, the QD-HS mixtures were dialyzed to separate free Cd2+ from intact QDs, followed by analysis of the solutions using inductively coupled plasma-mass spectrometry. Results suggested that degradation of QDs in the presence of HS did not occur within the period of incubation.
量子点（QD）纳米粒子的产量和使用量不断增加，人们开始担心含有 QD 的废物可能会污染水生和陆地生态系统。因此，研究 QD 与自然环境成分相互作用时的行为已成为研究热点。本研究采用毛细管电泳激光诱导荧光检测法，研究了两种水生腐殖质（HS）——苏湾河腐殖酸和富里酸存在时，羧酸或胺聚乙二醇（PEG）功能化 CdSe/ZnS QD 的荧光和电泳迁移率。结果表明，在与 HS 相互作用的初始阶段，QD 的荧光会增强，然后随着与 HS 的接触时间延长（>30 分钟），荧光会猝灭。还观察到，随着 HS 浓度的增加，QD 的电泳迁移率增加，这表明纳米颗粒的电荷与流体力学尺寸之比增加。为了确定 QD 与 HS 相互作用后是否发生降解，将 QD-HS 混合物进行透析，以将游离的 Cd2+与完整的 QD 分离，然后使用电感耦合等离子体质谱法对溶液进行分析。结果表明，在 HS 存在的情况下，QD 在孵育期内没有发生降解。
