Catalytic Polarographic Determination of Micro-amount of Arsenic in Complex Materials with Separation by Distillation

It was reported that micro-amount of arsenic in complex materials were determined by catalytic polarography in testing solution containing 5 mL of Te(Ⅳ)-H2SO4 solution and 5 mL of 150 g·L-1 of KI solution. Anodic scanning at the rate of 250 mV·s-1 and 2nd derivative of the measured polarographic wave were adopted in the determination. The sample (0.01-1.0 g) was dissolved in KClO3 (0.5 g), HF (5 drops) and HNO3 (5-10 mL), and As ion was separated by distillation. Linear relationship between values of peak current and mass concentration of As was obtained in the range within 0.4 mg·L-1. Twelve samples of ores were analyzed by the proposed method for their arsenic contents, giving results consistent with the known values. Values of recovery and RSD′s (n=6) found were in the ranges of 97%-100% and 2.3%-7.2%.