| Abstract: | The use of graphite-epoxy composite electrodes (GECE) as an alternative to mercury or modified electrodes for stripping voltammetry is presented. The effect of preconcentration time on the peak current was studied. It is shown, unlike traditional mercury electrodes, that the accumulation of lead using GECE does not yield a saturation current even at high preconcentration times of 30 min. A preconcentration time of 1 min was chosen as a compromise between analysis time and sensitivity. The peak current was increased by decreasing pH, the pH range 1-2 being the most sensitive. Concentrations as low as 1 ppb for lead and copper and 10 ppb for cadmium in standard solutions have been detected. Both analytical results and SEM characterisation confirm the behaviour of GECE as a complex microelectrode array at a rough surface. |
