Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand.
J Chromatogr A. 2011 Jul 8;1218(27):4213-8. doi: 10.1016/j.chroma.2010.12.040. Epub 2010 Dec 21.
Flow field-flow fractionation (Fl-FFF) with off-line electrothermal atomic absorption spectrometry (ETAAS) detection was developed and employed for particle size characterization of Ag NPs stabilized by citrate, pectin, and alginate. Citrate stabilized-Ag NPs were prepared from sodium borohydride reduction of silver nitrate. Sodium citrate was used as the capping agent to stabilize Ag NPs and prevent the aggregation process. Pectin stabilized- and alginate stabilized-Ag NPs were prepared from ascorbic acid reduction of silver nitrate. Pectin and alginate were used as the capping agent for pectin stabilized- and alginate stabilized-Ag NPs, respectively. Three types of Ag NPs were characterized by using FlFFF, zeta potentiometer, and TEM technique. The mean particle sizes of Ag NPs as characterized by FlFFF were 9 nm, 19 nm, and 45 nm for citrate stabilized-, pectin stabilized-, and alginate stabilized-Ag NPs, respectively, in deionized water. Further, FlFFF with ETAAS detection was employed to observe the aggregation of Ag NPs of various types in environmental water in the absence and presence of humic acid. Citrate stabilized-Ag NPs underwent aggregation more rapid than the pectin stabilized- and alginate stabilized-Ag NPs as the latter two types were sterically stabilized. Further, humic acid could prolong the stability of Ag NPs in the environment.
流动场流分级（Fl-FFF）与离线电热原子吸收光谱（ETAAS）检测相结合，用于对柠檬酸、果胶和海藻酸钠稳定的 Ag NPs 的粒径进行特征分析。柠檬酸稳定的 Ag NPs 是由硼氢化钠还原硝酸银制备的。柠檬酸被用作稳定剂来稳定 Ag NPs 并防止聚集过程。果胶稳定的和海藻酸钠稳定的 Ag NPs 是由抗坏血酸还原硝酸银制备的。果胶和海藻酸钠分别被用作果胶稳定的和海藻酸钠稳定的 Ag NPs 的稳定剂。使用 FlFFF、zeta 电位计和 TEM 技术对三种类型的 Ag NPs 进行了表征。FlFFF 分析的结果表明，在去离子水中，柠檬酸稳定的、果胶稳定的和海藻酸钠稳定的 Ag NPs 的平均粒径分别为 9nm、19nm 和 45nm。此外，还采用 FlFFF 与 ETAAS 检测相结合的方法，观察了在不存在和存在腐殖酸的情况下，不同类型的 Ag NPs 在环境水中的聚集情况。柠檬酸稳定的 Ag NPs 的聚集速度比果胶稳定的和海藻酸钠稳定的 Ag NPs 更快，因为后两种类型的 Ag NPs 受到空间位阻的稳定作用。此外，腐殖酸可以延长 Ag NPs 在环境中的稳定性。
