催化动力学光度法测定环境水样中痕量钴

Determination of trace cobalt in environmental water samples by catalytic kinetic spectrophotometry method

研究了催化动力学光度法测定痕量钴的方法。在硝酸介质中，痕量钴对过氧化氢氧化结晶紫褪色反应有催化作用，据此建立了测定痕量钴的新催化光度法。最佳测定条件为：0．2mol／L硝酸溶液用量为2．0mL，0．3mol／L过氧化氢溶液用量为2．5mL，0．1mmol／L结晶紫溶液用量为1．8mL，在90℃水浴下反应9min。方法线性范围0．2—10．0μg／L，检出限为0．088μg/L。对5．0μg／L Co（Ⅱ）测定的相对标准偏差为2．2％（n=11）。应用于环境水样中痕量钴的测定，结果令人满意。

A new catalytic kinetic spectrophotometric method for the determination of trace cobalt was studied. The method was based on the catalytic effect of Co（ Ⅱ ） on the oxidational discoloration of crystal violet with hydrogen peroxide in nitric acid. The optimum experimental conditions are determined, the amount of 0.2 mol/L nitric acid is 2.0 mL,the amount of 0.3 mol/L hydrogen peroxide is 2.5 mL,the amount of 0.1 mmol/L crystal violet is 1.8 mL, the reaction time is 9 min at 90 ℃. The determination range is 0.2 - 10.0 μg/L and the detection limit is 0. 088 μg/L. The relative standard deviation is 2.2% （ n = 11 ）. The method has been used to determine trace cobalt in environmental water samples with satis- factory results.