Abstract：The color reaction between 2-(5-cyano-2-pyridylazo)-5-dimethylaminoaniline (5-CN-PADMA) with cobalt was investigated and it was applied for determination of cobalt in actual samples. The experiments showed that cobalt (II) could react with 5-CN-PADMA in HAc-NaAc buffer solution at pH 4.5 to form stable complex with maximum absorption peak at 543nm. After acidification with 1.2mol/L HClO4, this complex was converted to a stable blue complex with two absorption peaks at 570nm and 609nm, respectively. Under optimized experimental conditions, it had a linear relationship between cobalt (II) with mass concentration in range of 0.04-0.60μg/mL and the absorbance sum at 570nm and 609nm. The linear correlation coefficient was 0.9998. The apparent molar absorptivity was ε=1.99×105 L·mol-1·cm-1. The proposed system was applied for the determination of trace cobalt in nickel ore and palladium-cobalt carbon catalyst, and the results were consistent with those obtained by flame atomic absorption spectrometry. The relative standard deviations (RSD, n=6) were between 0.5% and 0.6%.
霍燕燕, 王欢, 尹新华, 韩权, 杨晓慧. 2-(5-氰基-2-吡啶偶氮)-5-二甲氨基苯胺与钴的显色反应及其应用[J]. 冶金分析, 2019, 39(3): 54-57.
HUO Yan-yan, WANG Huan, YIN Xin-hua, HAN Quan, YANG Xiao-hui. Color reaction of cobalt (II) with 2-(5-cyano-2-pyridylazo)- 5-dimethylaminoaniline and its application. , 2019, 39(3): 54-57.
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