钴Ⅱ-三乙醇胺-H_2O_2-二甲苯蓝FF体系负催化光度法测定痕量钴

Determination of trace amounts of cobalt by nagative catalytic spectrophotometry using CoⅡ-triethanolamine-H_2O_2-xylene cyanol FF system

在碱性条件下,痕量钴 与三乙醇胺对H2O2氧化二甲苯蓝FF的反应有较强的负催化作用,钴含量与吸光度的增加值呈线性关系,据此建立了负催化光度法测定痕量钴的新方法。最大吸收波长λmax=638nm,表观摩尔吸光系数为1 2×105,25mL溶液中测定钴的线性范围为0～9μg。用于水样和茶叶中痕量钴的测定,结果满意。

In alkaline medium,based on the nagative catalytic effect of trace amounts of cobalt and triethanolamine on the oxidation of xylene cyanol FF by hydrogen peroxide and the linear relationship between cobalt content and the increment of absorbency,a new nagative catalytic spectrophotometric method for determination of trace amounts of cobalt was established.The maximum absorption wavelength is 638 nm,the apparent molar absorption coefficient is 1.2×10~5 L·mol^(-1)·cm^(-1),the linear range for the determination of cobalt is 0-9 μg/25 mL.The method has been applied to the determination of trace amounts of cobalt in water and tea with satisfactory results.