β-环糊精及阿拉伯树胶对铜-结晶紫-硫氰酸盐显色反应的增敏作用

Enhanced sensitivity effect of β-cyclodextrin and arabic gum on the color reaction of copper with sulfocyanate and crystal violet

研究了在β-环糊精(β-CD)和阿拉伯树胶存在下,在硫酸介质中,硫氰酸盐-结晶紫与铜的显色反应,建立了光度法测定铜的新方法;讨论了酸度、显色剂用量、表面活性剂和共存离子的影响,确定了最佳实验条件。结果表明:在25mL溶液中,铜量在0·08～7μg范围内符合比尔定律,检出限为1·0μg/L,该离子缔合物的最大吸收波长λmax=540nm,表观摩尔吸光系数ε540=2·22×105L·mol-1·cm-1。方法已用于自来水中铜的测定,相对标准偏差为1·5%,加标回收率为98·8%～100·1%。

Based on the eolour reaction of copper with sulfoeyanate and crystal violet（CV）,a new spec-trphotometric method for determination of copper in the presence of β-cyclodextrin and arabic gum is proposed. The factors such as acidity,reagent dosage,influence of surfactant and coexisting ions on the reaction were discussed and the optimal conditions were investigated. The maximum absorption of the complex was located at 540 nm and the apparent molar absorptivity was 2.22 × 10^5L·mol^-1cm^-1.. Beer＇s law was obeyed in the range of 0.08-7 μg/25mL for copper,and the detection limit was 1.0 μg/L. This method has been applied to the determination of trace copper in water with recovery of 98%-101% and RSD of 1.5%.