铬天青S胶束增溶分光光度法测定高纯氧化铋中微量铝

高纯氧化铋试样用硝酸溶解后,加入氢溴酸使铋生成易挥发的溴化铋除去,从而消除了铋对测定铝的干扰,在pH6.7的乙酸乙酸铵缓冲溶液中,在辛基酚聚氧乙烯醚存在条件下,铝与铬天青S生成稳定的三元配合物,其最大吸收波长为620nm,表观摩尔吸光系数为2.30×10⁵L/(mol·cm),铝在0～10μg/50mL范围内符合比耳定律,适用于高纯氧化铋中的微量铝的测定.

Determination of Trace Aluminum in High Pure Bismuth Oxide with Spectrophotometry by Micellar Solubilization of Chrome Azurol S

Photometric method is used to determinate aluminum in high pure bismuth trioxide. Bismuth disturbance is eliminated by volatilizing bismuth bromide with hydrobromic acid after the test sample is dissolved in nitric acid. Aluminum in the solution reacts with chrome azurol S to form a stable tribasic complex in a buffer solution (pH 6.7) of acetic acid and acetate ammoni um in the presence of octylphenol polyoxyethylene ether. The maximum absorbance is 620 nm with an apparent molar absorptivity of 2.30×10⁵ L/(mol·cm). Beer's law is obeyed in the concentration range of 0～10 μg/50 mL of aluminum. The method has been satisfactorily applied to the determination of trace aluminum in high pure bismuth oxide.