VOLTAMMETRIC DETERMINATION OF ARSENIC IN ZINC-OXIDE USED AS A FEED ADDITIVE

Cathodic stripping voltammetry at a hanging mercury drop electrode was applied for determination of arsenic in samples of zinc oxide intende d for use as a feed additive. The determinations were carried our in a cidic medium in the presence of Cu(II). The As(V) was prereduced to As (III) by potassium iodide and ascorbic acid at ambient temperature. Th e detection limit was 0.1 ng mL(-1). The feasibility of simultaneous d etermination of arsenic and cadmium in such analysis was also shown. T he electrothermal atomic absorption spectrometry was used as a referen ce method.