DETERMINATION OF ARSENIC BY CATHODIC STRIPPING VOLTAMMETRY AT A HANGING MERCURY DROP ELECTRODE

Arsenic (III), respectively arsenic(V) after the reduction were determ ined in model solutions and some inorganic and organic materials by fa st scan differential pulse cathodic stripping voltammetry and by direc t current cathodic stripping voltammetry with a rapid increase of pote ntial. The accumulation on a hanging mercury drop electrode followed b y cathodic stripping was carried out in 0.7-0.8 M HCl or 1-2 M H2SO4 s olutions containing Cu(II)-ions. Detection limits calculated from regr ession parameters was determined to be under 1 ng/ml for the samples c ontaining very low arsenic concentrations. The relative standard devia tion did not reach 8% for arsenic contents about of 5 ng/ml.