双波长标准加入法同时测定钴镍合金镀液中的钴(Ⅱ)和镍(Ⅱ)

Simultaneous Determination of Cobalt(Ⅱ) and Nickel(Ⅱ) in Co-Ni Alloy Plating Solution by Dual-Wavelength Standard Addition Spectrophotometry

在 p H5 .0的乙酸 -乙酸钠缓冲溶液和聚乙烯醇体系中 ,钴 ( )和镍 ( )可与 PAN试剂形成稳定的络合物。以钴 ( )的 5 80 nm和 6 2 6 nm为测定波长对 ,镍作标准加入组分 ,双波长标准加入法可同时测定试样中钴、镍的含量。镍在 0— 15 μg/2 5 m L,钴在 0— 10 μg/2 5 m L范围内遵从比耳定律。对镀液样品进行测定 ,镍、钴的相对标准偏差 (n=6 )分别 <0 .82 %和 <1.2 %。

A new dual-wavelength standard addition spectrophotometry for simultaneous determination of cobalt(Ⅱ) and nickel(Ⅱ)was established based on the reaction of cobalt(Ⅱ) and nickel(Ⅱ) with PAN to form stable complexes in pH 5.0 HAc-NaAc buffer medium and in the presence of polyvinyl alcohol.The maximum absorptions of the two complexes are located at 612nm and 578nm.A couple of wavelengths of cobalt complex,580nm and 626nm,were accurately selected as the measuring wavelengths,and nickel(Ⅱ)as standard-addition component.Beer's law is obeyed in the range of 0-15μg/25mL for Ni 2+ and 0-10μg/25mL for Co 2+ ,respectively.The method is simple,rapid and sensitive,and was used in simultaneous determination of Ni 2+ and Co 2+ in plating solution with relative standard deviations of less than 1.2% for Co 2+ and 0.82% for Ni 2+ .