原子吸收光谱法测定高纯稀土中的微量铜

A determination on trace copper of highly purity RE by atomic absorption spectrometry

摘要: 应用钨丝灯和原子吸收分光光度计(AAS)对胡椒基荧光酮(PIF)与铜的显色反应进行了研究。结果表明:在pH5.8 ~ 6.6的六次甲基四胺-HCl缓冲介质中和十六烷基三甲基溴化铵存在下, Cu²⁺与PIF形成稳定的1 :2的蓝紫色配合物。其最大吸收峰为585nm, 负峰为525nm。正负峰吸光度绝对值之和与Cu²⁺浓度线性相关, 铜的质量浓度在0 ~ 0.2μg ·mL^-1范围内符合比耳定律, 表观摩尔吸光系数ε_{585, 525}为1.56 ×10⁵ L·mol^-1 ·cm^-1。方法用于高纯稀土氧化物中微量铜的测定, 结果满意。

Abstract: The colour reaction between Cu²⁺ and piperonal fluorone(PIF)has been studied by using tungsten wire light and atomic absorption spectrophotometer.The study results show the blueviolet complex formed between Cu²⁺and piperonal fluorone(PIF)with(CH₂)₆N₄ -HCl buffer medium and CTMAB, the pH value is 5.8 ~ 6.6 and the proportion is 1 :2.The measuring and reference wavelengths are 585nm and 525nm respectively, the absorptivity is 1.56×10⁵ L· mol^-1 cm^-1.Beer′s law is obeyed in the range of 0~ 0.2 μg· m L^-1 for Cu²⁺.The above method has been applied in the determination of trace Cu²⁺ in highly pure RE oxides.