A method of precise coulometric titration of Au(Ⅲ)was studied with electrogenerating Fe(Ⅱ)-EDTA as titrant in Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc buffer solution.For the determination of gold in the range of 5.2 to 17.0mg ,the relative average errors and RSD of the results were≤0.03%(n=5),using potentiometric end point detection.The proposed method has been applied to the precise analysis of gold content in pure gold,gold alloys and jewelry with good selectivity.The theoretical basis for electrogeneration Fe(Ⅱ)-EDTA complex as a coulometric titrant was also discussed and a useful conclusion was obtained.%提出了在Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc缓冲溶液中利用电生Fe(Ⅱ)-ED-TA络合物精密库仑滴定Au的方法.采用电位法检测终点,测定范围在5.2～17.0mg Au时,相对平均误差和标准偏差≤0.03%.方法可用于纯金、金合金和首饰等材料中Au含量的精密分析,选择性很好.讨论了电生Fe(Ⅱ)-EDTA络合物作库仑滴定剂的理论基础,获得了有益的结论.
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