Analytical and Food Chemistry Department; Faculty of Chemistry; University of Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
Analytical and Food Chemistry Department; Faculty of Chemistry; University of Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
Talanta. 2019 Feb 1;193:176-183. doi: 10.1016/j.talanta.2018.09.092. Epub 2018 Sep 25.
A novel method for AuNPs/total Au speciation based on the combination of magnetic solid phase extraction and graphite furnace atomic absorption spectrometry (GFAAS) is described. Ascorbic acid enabled the quantitative extraction of both AuNPs and Au(III) by naked FeONPs, whereas a selective extraction of AuNPs was achieved in the presence of sodium thiosulfate. Experimental parameters influencing the extraction of both AuNPs and total Au, namely FeONPs mass, L-ascorbic acid concentration, pH, extraction time, sample volume, NaSO concentration and re-dispersion volume of magnetic solid phase prior to introduction in the graphite tube, were evaluated. Under optimal conditions, the proposed method yielded detection limits of 19.5 and 19.7 ng L for AuNPs and Au(III), respectively. Intraday repeatability and inter-day reproducibility were lower than 5.3% (N = 6) and 7.6% (N = 4) for both species, respectively. Enrichment factors over 196, corresponding to extraction efficiencies higher than 98%, were obtained for both species. Remarkably, non-significant differences in the extraction of AuNPs over a wide range of AuNPs sizes and morphologies with different capping agents were observed. The reported method was applied to the analysis of superficial waters, groundwater, seawater and artificial wastewater with good recoveries. The method represents a suitable alternative to other reported methodologies for AuNPs quantification in environmental waters at (ultra)trace levels.
一种基于磁固相萃取和石墨炉原子吸收光谱法（GFAAS）结合的新型 AuNPs/总金形态分析方法。抗坏血酸使裸 FeONPs 能够定量提取 AuNPs 和 Au(III)，而在硫代硫酸钠存在下可以选择性提取 AuNPs。实验参数影响 AuNPs 和总金的萃取，即 FeONPs 质量、L-抗坏血酸浓度、pH 值、萃取时间、样品体积、NaSO 浓度和磁性固相在引入石墨管之前的再分散体积。在最佳条件下，该方法对 AuNPs 和 Au(III)的检测限分别为 19.5 和 19.7ngL。两种物质的日内重复性和日间重现性均低于 5.3%（N=6）和 7.6%（N=4）。两种物质的富集因子均超过 196，萃取效率均高于 98%。值得注意的是，对于具有不同帽状剂的各种尺寸和形态的 AuNPs，其萃取没有明显差异。该方法已应用于地表水、地下水、海水和人工废水的分析，回收率良好。该方法代表了在痕量水平下分析环境水中 AuNPs 的另一种替代方法。
