Polarographic behavior of beryllium-aluminon complex in the presence of chlorate and determination of beryllium

In pH 7.5 Clark-Lubs buffer solution, the complex of Be(II)-aluminon can produce a sensitive polarographic wave at -0.77 V (vs. SCE). When potassium chlorate was added, the wave,height increased about 3 times and the peak potential moved to -0.73 V. The derivative wave height is linear with the concentration of beryllium in the range of 0.005 similar to 0.2 mg/L, the detection limit is 3.5 mu g/L. The adsorption and catalysis character of the wave was proved by the experiments. The mechanism of the electrode process was proposed. The composition of beryllium-aluminon complex was found to be 1:2. Aluminon in the complex was reduced and its product was then oxidized by potassium chlorate to reproduce the original ligand. A catalytic cycle was formed and the sensitivity was increased obviously. The method has been applied to the determination of Be in the rock and soil samples.