Determination of nickel and cobalt in refined beet sugar by adsorptive cathodic stripping voltammetry without sample pretreatment

Nickel and cobalt have been analysed in refined beet sugar at the mu g kg(- 1) level by adsorptive cathodic stripping voltammetry in the differential-p ulse mode (DPCSV) at the hanging mercury drop electrode (HMDE) as their dim ethylglyoxime complexes, M(DMG)(2). Measurements were directly carried out on untreated sugar solutions. The performance of the procedure was compared with electrothermal atomic absorption spectrometry (ETAAS) applied to dige sted sugar samples, and showed in general better accuracy. The procedure wa s applied to the determination of these toxic elements in refined beet suga r samples, and concentrations below 50 mu g kg(-1) nickel and 10 mu g kg(-1 ) cobalt were found, which are much lower than the toxic levels of these el ements. (C) 2000 Elsevier Science Ltd. All rights reserved.