铬(Ⅵ)-溴酸钾-乙基紫催化光度法测定水中痕量铬(Ⅵ)

Determination of Trace Chromium(Ⅵ)in Water by Catalytic Spectrophotometric Method with Chromium(Ⅵ)-Potassium Bromate-Ethyl Violet System

在磷酸介质中，利用铬（Ⅵ）对溴酸钾氧化乙基紫褪色反应有灵敏的催化作用，建立了测定痕量铬（Ⅵ）的新型催化光度法，考察了该褪色反应的最佳条件。在反应温度85℃、反应时间5min、以醋酸钠作抑制剂的条件下，体系可稳定60min以上，测定波长为600nm，方法的检出限为1×10^-9g/mL，线性范围为0．004～0．094μg/mL，相对标准偏差小于2.5％，加标回收率为97．0％-101．5％。该法简便、灵敏、选择陛好，用于水样中痕量铬（Ⅵ）的测定，结果令人满意。

A new catalytic spectrophotometric method for determination of trace chromium （ Ⅵ ） was established based on the sensitive catalytic effect of chromium （ Ⅵ ） on the oxidation decoloration of ethyl violet by potassium bromate in the medium of phosphoric acid. The optimum conditions of decoloration reaction were studied. When the reaction temperature is 85 ℃, the reaction time is 5 min and sodium acetate is used as inhibitor, the reaction system can keep stable for more than 60 min. The determination wavelength is 600 nm. The detection limit is 1 × 10 ^-9 g/mL. The linear rang is 0.004 - 0.094 μg/mL. The relative standard deviation is less than 2.5 %. The recovery of marked compound is 97%-101.5%. This method is convenient, sensitive and has a good selectivity. It can by used in determination of trace chromium （ Ⅵ ） in water with good results.