抄録
Beryllium formed a red complex (the absorption maximum : 525 nm) with Chromazurol S (GAS) in the presence of zephiramine at pH 10, and the red color developed was applied to the spectrophotometric determination of beryllium. Recommended procedure is as follows : To a sample solution containing less than 3 μg of beryllium, add 0.5 ml of EDTA solution (0.05 M), 1 ml of ammonium chloride solution (0.5 M), 1.0 ml of CAS solution (2 × 10-3 M) and 5 ml of zephiramine solution (1.35 × 10-2 M). Adjust pH to 10 with sodium hydroxide solution (0.25 M) and dilute to 25.0 ml with water. Measure the absorbance at 525 nm against the reagent blank. Beer's law was obeyed for (0.041.3) × 10-5 M of beryllium. The apparent molar absorptivity was 5.35 × 104 dm3 mol-1 cm-1. Less than 1 mg of Mn (II), Cd (II), Zn (II), Al(III), Mo(VI), 0.2 mg of Pb(II), Ni(II), Co (II), Cu (II), Fe (III), As (III), 0.1 mg of Sn (II), V (V), and 0.05 mg of Cr (III), Ti (IV) did not interfere. Less than 200 mg of chloride and sulfate, and 12 mg of nitrate did not interfere. This method had following merits compared with the CAS-cationic surfactants methods at pH 56 : anions within the range of concentrations described above did not interfere, and small differences in pH between the sample and the reagent blank solution did not affect the absorbances.
