铬(Ⅵ)—溴酸钾-偶氮胂Ⅰ催化光度法测定水中痕量铬(Ⅵ)

Catalytic Spectrophotometric Determination of Trace Cr (Ⅵ) Based on the Cr (Ⅵ)-Potassium Bromate-arsenazo Ⅰ System in Water Samples

基于在乙酸—乙酸钠缓冲介质中,铬(Ⅵ)对溴酸钾氧化偶氮胂Ⅰ的催化作用,建立了测定水中微量铬的新方法,研究了影响催化褪色反应速度的最佳条件,方法的检出限4.8×10-7g/L,线性范围为0.12～2.2μg/25mL铬(Ⅵ)。多数常见的离子均不干扰测定。用于水中微量铬的测定,快速、准确、简便。

A new kinetic spectrophotometric method for the determination of trace amounts of Cr （Ⅵ） is described, based on the catalytic effect of trace Cr （Ⅵ） on the oxidation of arsenazo I by potassium bromate in pH=5 Hac- NaAc buffer solution. The optimum conditions influencing the rate of reaction were obtained. The detection limit for Cr （Ⅵ） is 4.8×10^-7 g/L. The linear range of the determination is 0.12 - 2.2 μg/25ml for Cr （Ⅵ）. Common foreign ions have no interference on the determination of Cr （Ⅵ）. This method was rapid, accurate and convenient for the determination of trace Cr （Ⅵ） in water samples.