胭脂红褪色光度法测定锌镍合金镀液中的镍含量

Determination of Ni^(2+) content in Zn-Ni alloy electroplating solution with carmine red fading spectrophotometry

在pH=5 4的六次甲基四胺-盐酸缓冲溶液、100℃恒温水浴中,Ni2+能催化双氧水氧化胭脂红褪色,据此提出采用胭脂红褪色光度法测定锌镍合金镀液中的镍含量。确定了适宜的试验条件,其中测定波长为518nm。讨论了该镍催化反应的表观活化能以及杂质离子对测定结果的影响,并给出了某电镀厂碱性锌镍合金镀液中镍含量的测定结果。该方法简便,准确度高,能满足生产中快速测定的要求。

In the buffer solution of hexamethyle netetramine-hydrochloric acid of pH=5.4 with water bath of (100 ℃,) carmine red can be oxidized to fade by hydrogen peroxide, in which Ni^(2+) is used as catalyst, and thereby carmine red fading spetrophotometry was promoted to measure the Ni^(2+) content in Zn-Ni alloy electroplating solution. The relevant experimental conditions were obtained and the suitable wavelength was 518 nm. The influences of the apparent activation energy of Ni^(2+) catalytic reaction and the impurity ions in the solution on the testing results were discussed. The Ni^(2+) content in the alkaline Zn-Ni alloy electroplating solution of one electroplating factory was tested. The results show that this method is easy and highly accurate, and can meet the demand of fast measurement in production.