催化动力学光度法测定环境水样中痕量钴

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:0.2 mol/L硝酸溶液用量为2.0 mL,0.3 mol/L过氧化氢溶液用量为2.5 mL,0.1 mmol/L结晶紫溶液用量为1.8 mL,在90℃水浴下反应9 min。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。

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

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 satisfactory results.