Simultaneous Determination of Palladium and Cobalt in Electroplating Solution and Electroplated Layer by spectrophotometry
在 ＰＨ＝ ４．５的 ＨＡＣ－ＮａＡｃ介质中，钴和钯都能与 ２－［２－（６－甲基苯并噻唑）偶氮］５－［Ｎ－甲基．Ｎ．乙羧基］苯甲酸（简称ＭＣＢ）形成络合物。在λ＝７１０ ｎｍ处 Ｃｏ－ＭＣＢ不吸收；在 ６１０．５ｎｍ处Ｄｏ－ＭＣＢ有最大吸收，而Ｐｄ－ＭＣＢ也有一定的吸收值。利用这一差异，可在６１０．５ ｎｍ处测定 Ｐｄ和 Ｃｏ的合量，而在７１０ ｎｍ处测定 Ｐｄ的含量，再利用系数法算出 Ｃｏ的含量。测定的线性范围分别为 ０．２～４．０ ｍｇ／Ｌ（对Ｐｄ）和０．４～２．２５ ｍｇ／Ｌ（对 Ｃｏ），相对标准偏差均小于４％，回收率在９１％－１０８％之间。本方法简便、快捷，可用于电镀液和镀层中钯和钴的同时测定。In the HAc-NaAc medium(pH = 4. 5), Co(Ⅱ) and Pd(Ⅱ) ions could react with 2-[2- (6methylbenzothiazole) azo- ] -5- [ N-methyl- N- acetyl ] benzoic acid (MCB ) to form Co- MCB and Pd- MCB complexes. The experimental results showed that both Co-MCB and Pd-MCB had absorption Peaks at 610.5 nm, and only Pd-MCB had an obvious absorption Peak at 710 nm, therefore, the contents of Co and Pd can be determined simultaneously by measuring the absorbance of Pd at 710 run and the total absorbance at 610.5 nm. The linear ranges were 0.2 ~ 4.0 mg/L (for Pd ) and 0.4 ~ 2.25 mg/L (for Co). The relative standard deviations were less than 4%, and the recoveries were 91% ~ 108%. The method was rapid, simple, and it has been applied to detendne the Pd and Co in the electroplating solution and electroplated layer.