Underpotential deposition of lead at silver electrodes manufactured from compact discs and its determination in environmental water samples

The present paper describes the facile manufacture of silver electrodes from compact discs for the anodic stripping voltammetric determination of lead. The voltammetric behaviour of Pb in 0.1 M HCl was examined by cyclic voltammetry. Using a starting potential of 0.0 V and switching potential of -0.60 V a distinct underpotential deposition (UPD) process was recognizable resulting in a reduction process at -0.43 V, with a corresponding stripping peak at -0.37 V on the return positive going scan. If a more negative switching potential of -0.90 V was used a further stripping peak is seen with an Ep of -0.49 V, indicative of the stripping of a bulk deposited Pb layer. The possibility of using this UPD behaviour for the determination of trace levels using this medium was examined by anodic stripping voltammetry using the differential pulse waveform in the measurement step. The developed method was evaluated by carrying out Pb determinations on spiked and unspiked roof drainage water. The unfortified sample was found to contain 99.6 ng /mL. The percentage recovery gained for the same sample fortified with 100 ng/mL was calculated to be 95 % with an associated coefficient of variation of 2.7 %.