Polarographic determination of small amounts of nickel and cobalt in glasses and in some glass raw materials

Abstract

Two very sensitive methods for the determination of trace amounts of nickel and cobalt by means of adsorption stripping polarography using a hanging mercury drop electrode are described. For the accumulation the sorption properties of Ni(II) and Co(II) complexes with dimethylglyoxime or of the Co(III) complex with 1-nitroso-2-naphthol in the medium ammonia-ammonium chloride buffer was utilized. The current of the reduction of Ni(II) and Co(II) to metal or of Co(III) to Co(II) in the range from 1 to 20 μg/l was measured by fast-scan differential-pulse polarography. Using the methods described, the nickel and cobalt contents in the glass and in some glass raw materials of 0.001 to 0.00001 % can be determined with a relative error which does not exceed ± 10 %.