RESUMO
A novel approach of using a gold disc microelectrode to analyze sweat samples for copper ions by anodic square wave stripping voltammetry (SW stripping voltammetry) is described. Sweat was collected from the lower back of four subjects after physical exercise and the sample volume required for the determinations was 100 µL. Under the optimized conditions, the calibration plot was linear over the range 1-100 µmol L(-1) Cu(II) with a limit of detection of 0.25 µmol L(-1). The precision was evaluated by carrying out five replicate measurements in a 1 µmol L(-1) Cu(II) solution and the standard deviation was found to be 1.5%. Measurements were performed by inserting the microelectrode into sweat drops and Cu(II) concentrations in the analyzed samples ranged from 0.9 to 28 µmol L(-1). Values obtained by the proposed voltammetric method agreed well with those found using graphite furnace atomic absorption spectroscopy (GFAAS).