Cadion-Cd(Ⅱ)-PVA-光度法测定微量镉

A spectrophotometric method for determination of trace cadmium with Cadion-Cd(Ⅱ)-PVA

研究了在KOH介质中，在聚乙烯酸（PVA）存在下Cd（Ⅱ）离子与1－（4－硝基苯基）－3－[4－（苯基偶氮）苯基]－三氮烯（Cadion）形成1：2配合物，其配合物最大吸收位于530nm处，而使空白试剂最大吸收波长530nm处吸光度下降.利用Cadion试剂的褪色测定微量镉.该法测镉的表观摩尔吸光系数ε530为1．57×105L·mol-1·cm-1，镉含量在0～12μg/25mL范围内符合比尔定律.方法应用于铅渣中微量镉的测定，结果满意．

Spectrophotometric determination of trace cadmium (Ⅱ) has been Studied in the KOH medium and in the presence of polyvinyl alcohol (PVA). Chdmium(Ⅱ) reads with 1-(4-nitrophenyl)-3-(4-Phenylazophenyl)-triazen[Cadion] to form the complex. the ratio of cadmium to Cadion in the complex is 1:2. The maximum absorbance of complex is at 530nm .. Its apparent molar absorptivity is 1. 57×105 L·mol-1·cm-1. Beer's Law is obeyed in the range of 0~12μg/25 mL for Cd(Ⅱ). The proposed method has been applied to the determination of Cadion in lead dregs with Satisfactory results.