薄膜梯度扩散-原子吸收光谱法富集测量水中痕量镉

Determination of Cd^(2+) in Water by the Diffusive Gradients in Thin-Films Technique Combined with Atomic Absorption Spectrometry

建立了薄膜梯度扩散-原子吸收光谱(DGT-AAS)法富集测量水中痕量镉的分析方法。先以海藻酸钠(SA)溶液为结合相的DGT技术(SA DGT)原位分离富集水中Cd^(2+),再以AAS法测定DGT结合相中镉的含量,最后依据DGT方程计算水中Cd^(2+)浓度。DGT-AAS法测得配制水中Cd^(2+)的回收率为95.6%~102.7%,相对标准偏差(RSD)为1.5%~3.1%;测得河水和人工湖水中加标Cd^(2+)的DGT有效态分数分别为22.46%和15.19%。当采样时间为48h,SA DGT对水中Cd^(2+)的富集倍数为20倍,可显著降低分析方法的检测限,实现水中痕量Cd^(2+)的定量检测。

Cd^（2＋）in water was pre-concentrated by the diffusive gradients in thin-films（DGT） technique with sodium alginate（SA） as binding phase（SA DGT） and measured by atomic absorption spectrometry（ASS）. The recoveries of Cd^（2＋）in the synthetic solutions measured by the DGT-ASS method were 95. 6% ~ 102. 7%,with RSD1. 5% ~ 3. 1%. The DGT-labile fractions of Cd^（2＋）in a river and a lake were 22. 46% and 15. 19%,respectively.The enrichment factor of Cd^（2＋）pre-concentrated by SA DGT was 20（deployment time 48h）,and the detection limit of the analytical method can be significantly reduced. Therefore,the DGT-AAS method can be used to measure trace Cd^（2＋）in water.