铬天青R分光光度法测定铝土矿中的铍

建立了用铬天青R分光光度法测定铝土矿中铍的方法。700℃下用氢氧化钠碱熔法分解铝土矿,以8-羟基喹啉、酒石酸、EDTA作为掩蔽剂,在pH 9~10的氨水-氯化铵介质中,铍与铬天青R、溴化十六烷基三甲基胺(CTMAB)生成三元红色络合物,在波长552 nm处有最大吸收。方法的特征浓度为0.031μg/(mL.1%),摩尔吸光系数ε=1.25×105,标准偏差为0.000 7μg/mL,回收率为97.6%,铍量在0~0.06μg/mL内符合比耳定律。方法简便,准确度好,灵敏度高,结果令人满意。

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.