光度法测定水中微量镉

Spectrophotometricdetermination of trace cadmium in water

在 pH为 9的硼砂 -盐酸缓冲溶液中 ,DSPCF与镉生成蓝色络合物 ,最大吸收波长为 6 10nm ,测得表观摩尔吸光系数为 5 .76× 10 4L/ (mol·cm )。镉量在 0 1.6mg/L内符合比耳定律。采用甲基膦酸二甲庚脂 -HBr体系萃取色层分离微量镉 ,以提高方法的选择性 ,该法用于测定水中微量镉 。

The blue complex of cadmium(Ⅱ) with 1,5-di-(2-hydroxy-5-sulfophenyl)-3-cyanoformazan disodium salts (DSPCF) is formed in a buffer solution of borax-hydrochloric acid(pH 9). The complex has a maximum absorption wavelength at 610 nm. The apparent molar absorptivity is 5.76×10 4 L/(mol·cm). The trace cadmium is extrasted with di-(1-methylheptyl) methylphosphonate-HBr by chromatography separation,to improve the selectivity. The method has been applied to the determination of trace cadmium in water with satisfactory results.