A simple, sensitive and accurate procedure for the determinations of trace amounts of beryllium has been developed, based on solid-phase spectrophotometry. Beryllium reacts with aurintricarboxylic acid (ATCA) in the presence of ethylene-diaminetetraacetic acid to give a complex with a high molar absorptivity (1.50×107 l mol−1 cm−1), which is fixed on a dextran-type anion-exchange gel (Sephadex DEAE A-25). The absorbance of the gel, at 575 and 750 nm, packed in a 1.0 mm cell, is measured directly. Calibration is linear over the range 0.03–1.0 μg l−1 with RSD of <2.4% (n=8.0). The detection and quantification limits of the 500 ml sample method are 6.0 and 20 ng l−1 on using 90 mg. For 1000 ml sample the detection and quantification limits are 5.0 and 17 ng l−1 using 45 mg exchanger. Increasing the sample volume can enhance the sensitivity. The proposed methods have been applied to the determination of beryllium in tap, mineral and well water using the standard addition technique with recoveries of 100.13±0.61, 99.47±1.41 and 100.10±1.53, and concentration levels of 0.032, 0.221 and 10.92 μg l−1, respectively. |
