污水中镉含量的分光光度法测定

Determination of Cadmium in Sewage by Spectrophotometry

选用镉-碘化钾-罗丹明B多元络合物显色体系,分光光度法测定污水中镉的含量.研究结果表明:向待测镉标准溶液中加入1.0 mol/L硫酸溶液3.0 m L,碘化钾-抗坏血酸溶液4.0 m L和10 g/L聚乙烯醇-1750溶液2.0 m L,加入显色剂0.5 g/L罗丹明B溶液1.8 m L,摇匀放置10 min后,在600 nm波长处测定吸光度,镉的质量浓度在0~1.0 mg/L范围内符合朗伯-比尔定律,标准曲线相关系数R^2为0.993 3,加标回收率为98.75%~102.50%.

Cadmium-iodide-rhodamine B complex color system was established for the determination of the content of cadmium in wastewater using spectrophotometric method.The results show that 3.0 ml of sulfuric acid solution（1.0 mol / L）,4.0 ml of potassium iodide and ascorbic acid solution and 2.0 ml of polyvinyl alcohol-1750 solution（ 10 g / L） are added to the cadmium standard solutions,and then 1.8 m L of chromogenic agent rhodamine B solution（0.5 g / L） is added.The solution is shaked well for determination of absorbance in 600 nm after 10 minutes.The relationship between the absorbance and cadmium concentration follows Lambert Beer law in the range of 0 ~ 1.0 mg / L.Correlation coefficient R^2 of standard curve is 0.993 3,and recovery rates of standard substances are 98.75%~102.50%.