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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。
An analytical method for the determination of trace cadmium in water samples by gradient diffusion-atomic absorption spectrometry (DGT-AAS) was established. Cd 2+ in water was firstly separated and enriched in situ by DGT (SA DGT) method with sodium alginate (SA) as the binding phase. The content of cadmium in the DGT binding phase was determined by AAS method and finally calculated by DGT equation Water Cd ~ (2+) concentration. The recoveries of Cd 2+ in the prepared water were 95.6% -102.7% and the relative standard deviations (RSDs) were 1.5% -3.1% by DGT-AAS method. +) DGT effective state scores were 22.46% and 15.19%. When the sample time is 48h, the SA DGT concentration of Cd2 + in water is 20 times, which can significantly reduce the detection limit of the analytical method and achieve the quantitative detection of trace Cd2 + in water.