Centre for Aquatic Pollution Identification and Management (CAPIM), School of Chemistry, The University of Melbourne, Victoria 3010, Australia.
FI-TRACE Group, Department of Chemistry, Faculty of Science, University of the Balearic Islands, Carretera de Valldemossa km 7.5, E-07122, Palma de Mallorca, Spain.
Anal Chim Acta. 2017 Jul 4;975:1-10. doi: 10.1016/j.aca.2017.05.001. Epub 2017 May 5.
A hybrid and compact flow system for automatic assessment of trace level concentrations of bioaccessible mercury in different phases of environmental solid samples with high organic load is described for the first time. It integrates dynamic sequential extraction with on-line digestion of the extracts and atomic fluorescence spectrometric detection of their total bioaccessible mercury concentration. Four extractants (i.e. deionized water, HNO solution, KOH solution and solution containing both NaS and KOH) are applied sequentially to a solid sample packed in a column to release four bioaccessible Hg fractions (i.e. water soluble, exchangeable, organic matter associated, and sulphide bound Hg). Important advantages of the newly developed on-line method compared to its batch-wise counterpart include significant reduction in the time for acquisition of the dynamic extraction data (e.g. duration of 14 h versus 120 h for the batch-wise method), evaluation of the kinetics of release of the bioaccessible mercury fractions, and minimization of matrix interferences and potential re-adsorption of the extracted mercury species. The trueness of the method was assessed by applying it to two reference materials with relatively high organic matter content (river sediment AGAL-10 and biosoil AGAL-12). The sums of the Hg concentrations in the four bioaccessible fractions and the residual fraction of the two reference materials were found to differ from the corresponding certified values by only 1.8% and 3.8%, respectively.
首次描述了一种用于自动评估高有机负荷环境固体样品中痕量生物可利用汞浓度的混合式紧凑型流动系统。该系统将动态顺序提取与在线提取消化以及原子荧光光谱法检测其总生物可利用汞浓度相结合。将四种萃取剂（即去离子水、HNO3溶液、KOH 溶液和含有 Na2S 和 KOH 的溶液）依次应用于填充在柱中的固体样品，以释放四种生物可利用的 Hg 级分（即水溶性、可交换性、有机物结合和硫化物结合 Hg）。与批处理方法相比，新开发的在线方法具有显著优势，包括大大缩短了动态提取数据的采集时间（例如，批处理方法为 120 小时，而在线方法为 14 小时）、评估生物可利用汞级分释放的动力学、以及最大限度地减少基质干扰和潜在的提取汞物种的再吸附。该方法的准确性通过应用于两种具有较高有机物含量的参考物质（河流沉积物 AGAL-10 和生物土壤 AGAL-12）进行评估。两种参考物质的四个生物可利用级分和残余级分的 Hg 浓度总和与相应的认证值相差仅为 1.8%和 3.8%。
