還元剤添加示差原子吸光分析法によるCr(III), (IV) の定量とクロムめっき浴分析への応用

抄録

A previous papers reported on the enhancing effects of metal hydrides for the determination of metals that require high atomization temperature such as beryllium salt by flameless atomic absorption spectrometry in N, N-dimethylformamide (DMF).
The present paper proposes a method of quantitative estimation of mixing ratios in mixed solutions chromium (III) and (VI) ions by flameless atomic absorption spectrometry, utilizing the different effects lithium hydride and sodium boro hydride by in DMF.
That is to say the relation between increased sensitivity and the amount of lithium hydride added differed for chromium (III) and chromium (VI) ion. A calibration curve was drawn for each ion concentration, and the ratio of chromium (III) and chromium (VI) ions in the solution was determined by using the difference in the effects of lithium hydride on the two ions. The proposed method provided a satisfactory analytical result for chromium (III) and (VI) in general chromium plating baths.
The coefficient of variation by this method was 4.4% (n=5) for a mixed ion solution containing 0.5ppm chromium.