Environmental Futures Centre, Griffith School of Environment, Griffith University Gold Coast campus , Queensland 4222, Australia.
Anal Chem. 2014 Jan 7;86(1):427-34. doi: 10.1021/ac402247j. Epub 2013 Dec 4.
A new diffusive gradients in thin films (DGT) technique with a mixed binding layer (Chelex-100 and the titanium dioxide based adsorbent Metsorb) is described for the simultaneous measurement of labile trace metal (Mn, Co, Ni, Cu, Cd, and Pb) and oxyanion (V, As, Mo, Sb, W, and P) concentrations in freshwater and seawater. The mixed binding layer (MBL) DGT technique was evaluated against the Chelex-DGT and Metsorb-DGT techniques, and all elution efficiencies and diffusion coefficients have been remeasured for the above analytes. Diffusion coefficients (D) measured using MBL-DGT generally agreed well with those measured by Chelex-DGT (DMBL/DChelex = 0.97-1.05), Metsorb-DGT (DMBL/DMetsorb = 0.97-1.01), and diffusion cell experiments. The measurement of trace metals and oxyanions by MBL-DGT was independent of pH (5.03-8.05) and ionic strength (I = 0.001-0.7 mol L(-1)). MBL-DGT accurately measured the concentration of trace metals and oxyanions in synthetic freshwater (CMBL/CSol = 0.82-1.18) over the 4 day deployment and also agreed well with Metsorb-DGT (CMBL/CMetsorb = 0.84-0.94) and Chelex-DGT (CMBL/CChelex = 0.88-1.11) measurements. In synthetic seawater, MBL-DGT accurately measured the concentration of metals and oxyanions (CMBL/CSol = 0.85-1.12) over 4 days, with the exception of Mo-none of the DGT techniques were capable of measuring Mo in seawater. MBL-DGT measured the Mn concentration accurately over the entire 4 day period, whereas Chelex-DGT only measured Mn accurately up to 2 days. The MBL-DGT method described in this study offers significant advantages over the ferrihydrite-Chelex-DGT method reported previously. These advantages include the commercial availability of both Metsorb and Chelex-100, the higher accuracy of Metsorb for measuring some oxyanions in freshwater and seawater, and the possibility of measuring Fe, which would not be possible using the Chelex-ferrihydrite binding layer.
一种新的薄膜扩散梯度（DGT）技术，采用混合结合层（Chelex-100 和基于二氧化钛的吸附剂 Metsorb），用于同时测量淡水和海水中的痕量金属（Mn、Co、Ni、Cu、Cd 和 Pb）和含氧阴离子（V、As、Mo、Sb、W 和 P）的浓度。混合结合层（MBL）DGT 技术与 Chelex-DGT 和 Metsorb-DGT 技术进行了评估，并且已经重新测量了所有洗脱效率和扩散系数。使用 MBL-DGT 测量的扩散系数（D）通常与使用 Chelex-DGT（DMBL/DChelex = 0.97-1.05）、Metsorb-DGT（DMBL/DMetsorb = 0.97-1.01）和扩散池实验测量的扩散系数一致。MBL-DGT 测量痕量金属和含氧阴离子的浓度与 pH（5.03-8.05）和离子强度（I = 0.001-0.7 mol L(-1)）无关。MBL-DGT 在 4 天的部署期间准确测量了合成淡水中痕量金属和含氧阴离子的浓度（CMBL/CSol = 0.82-1.18），并且与 Metsorb-DGT（CMBL/CMetsorb = 0.84-0.94）和 Chelex-DGT（CMBL/CChelex = 0.88-1.11）测量结果吻合良好。在合成海水中，MBL-DGT 在 4 天内准确测量了金属和含氧阴离子的浓度（CMBL/CSol = 0.85-1.12），但钼除外-没有一种 DGT 技术能够测量海水中的钼。MBL-DGT 在整个 4 天期间准确测量了 Mn 的浓度，而 Chelex-DGT 仅在 2 天内准确测量了 Mn 的浓度。与之前报道的 Ferrihydrite-Chelex-DGT 方法相比，本研究中描述的 MBL-DGT 方法具有显著优势。这些优势包括 Metsorb 和 Chelex-100 的商业可用性、Metsorb 用于测量淡水和海水中某些含氧阴离子的更高准确性，以及测量 Fe 的可能性，这是使用 Chelex- Ferrihydrite 结合层不可能实现的。
