Determination of Beryllium in Bauxite Samples by Chrome Azurol R Spectrophotometry

A method for the determination of Be in bauxite samples by chrome azurol R spectrophotometry was established. Samples were decomposed by sodium hydroxide alkali fusion at 700℃. In the medium of ammonia-ammonium chloride at pH 9~10 and using 8-hydroxyquinoline, tartaric, and EDTA as masking agents, Be reacts with chrome azurol R and CTMAB and forms a red ternary complex. The maximum absorption of the complex is at wavelength of 552 nm with characteristic concentration of 0.031 μg /(mL·1%) and molar absorptivity of 1.25×10⁵. Beer's law is obeyed in a concentration range of 0~0.06 μg/mL for beryllium. The recovery of the method is 97.6% with standard deviation of 0.0007 μg/mL. The method provides the advantages of simple operation, high sensitivity and accuracy, and has been applied to the determination of Be in bauxite samples with satisfactory results.