薄膜梯度扩散-原子吸收光谱法富集测量水中痕量镉

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。

Determination of Cd2 in water by the diffusive gradients in thin-films techniquecombined with atomic absorption spectrometry

Cd₂ 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 Cd₂ in the synthetic solutions measured by the DGT-ASS method were 95.6% ~ 102.7% with relative standard deviation (RSD) 1.5% ~ 3.1%. The DGT-labile fractions of Cd₂ in a river and a lake were 22.46% and 15.19%, respectively. The enrichment factor of Cd₂ 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 Cd₂ in water.