二溴对甲偶氮羧光度法测定锌钴合金镀液中的钴

研究了显色剂二溴对甲偶氮羧与钴的显色反应。pH=10的柠檬酸铵–氨水溶液中,钴与二溴对甲偶氮羧反应形成蓝色配合物,其最大吸收波长为660nm,表观摩尔吸光系数为1.77×104L/(mol·cm)。25mL溶液中的钴含量为0~80μg,符合比尔定律。该方法可用于锌钴合金镀液中钴的直接测定,相对标准偏差为1.4%~1.9%,回收率为98%~102%。

Spectrophotometric determination of cobalt in zinc-cobalt alloy plating solution with dibromomethyl carboxyazo

The chromogenic reaction between the reagent dibromomethyl carboxyazo and cobalt was studied. In an ammonium citrate and ammonia solution with pH 10, cobalt reacts with the reagent to form a blue complex which exhibits an absorption maximum at 660 nm with a apparent molar absorptivity of 1.77 × 10~4 L/(mol·cm). Beer's law was obeyed in the range of 0-80 μg/(25 mL) for cobalt. The proposed method has been applied to direct determination of cobalt in zinc-cobalt alloy plating solution with RSD between 1.4% and 1.9% and recovery between 98% and 102%.