Wang Yan, Ding Shiming, Shi Lei, Gong Mengdan, Xu Shiwei, Zhang Chaosheng
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Anal Chim Acta. 2017 Jun 15;972:1-11. doi: 10.1016/j.aca.2017.04.007. Epub 2017 Apr 10.
A new method for the simultaneous measurements of eight cations [Fe(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)] and eight oxyanions [P(V), V(V), Cr(VI), As(III)/As(V), Se(VI), Mo(VI), Sb(V), and W(VI)] was established in this study using the diffusive gradients in thin films (DGT) technique with an improved ZrO-Chelex binding gel. The binding kinetics of each analyte in a mixed solution indicated a rapid uptake on the ZrO-Chelex gel. The anions exhibited slower absorption rates compared to the cations, which did not affect the DGT uptake. Stable elution efficiencies for these cations and anions were obtained based on a two-step extraction procedure using 1.0 M HNO for elution of the cations followed by a mixed solution containing 0.2 M NaOH and 0.5 M HO for elution of the anions. Simultaneous measurements of the cations and anions with the ZrO-Chelex DGT were validated in mixed solutions and found to be independent of solution pH (5-9) and ionic strength (2-3 mM to 750 mM). The capacities of the ZrO-Chelex DGT for single measurements of Fe(II), P(V), Cd(II), As(III), and As(V) were determined at 99.5, 127.6, 301.2, 33.3, and 87.4 μg cm. Except for Se(VI) in seawater, accurate measurements of all of these cations and anions in natural freshwater and seawater were obtained using the ZrO-Chelex DGT. The performance of this technique for simultaneous measurements of 16 elements was also tested in sediments.
本研究采用改进的ZrO-Chelex结合凝胶的薄膜扩散梯度（DGT）技术，建立了一种同时测定8种阳离子[Fe(II)、Mn(II)、Co(II)、Ni(II)、Cu(II)、Zn(II)、Cd(II)和Pb(II)]和8种含氧阴离子[P(V)、V(V)、Cr(VI)、As(III)/As(V)、Se(VI)、Mo(VI)、Sb(V)和W(VI)]的新方法。混合溶液中各分析物的结合动力学表明，其在ZrO-Chelex凝胶上的吸附迅速。与阳离子相比，阴离子的吸收速率较慢，但这并不影响DGT的吸附。基于两步萃取程序，获得了这些阳离子和阴离子稳定的洗脱效率，先用1.0 M HNO洗脱阳离子，然后用含有0.2 M NaOH和0.5 M HO的混合溶液洗脱阴离子。用ZrO-Chelex DGT同时测定阳离子和阴离子在混合溶液中得到验证，且发现其不受溶液pH值（5-9）和离子强度（2-3 mM至750 mM）的影响。ZrO-Chelex DGT单次测定Fe(II)、P(V)、Cd(II)、As(III)和As(V)的容量分别为99.5、127.6、301.2、33.3和87.4 μg cm。除海水中的Se(VI)外，使用ZrO-Chelex DGT可准确测定天然淡水和海水中的所有这些阳离子和阴离子。该技术同时测定16种元素的性能也在沉积物中进行了测试。
