Microwave-enhanced anodic stripping detection of lead in a river sediment sample. A mercury-free procedure employing a boron-doped diamond electrode

Microwave activation of electrochemical processes has recently been introdu ced as a novel technique for the enhancement and control of processes at th e electrode-solution interface and is employed here to improve the analytic al detection of Pb2+. Instead of the conventional mercury-based accumulatio n and stripping procedure, mercury-free boron-doped diamond electrodes are employed. The deposition and anodic stripping detection by square-wave volt ammetry of Pb2+ in a 0.1 M HNO3 solution is shown to be strongly enhanced b y microwave activation at boron-doped diamond electrode. The temperature at the electrode-solution interface is calibrated with reversible redox coupl e Fe3+/Fe2+ (4 mM Fe3+, 4 mM Fe2+) in 0.1 M HNO3 and a standard addition pr ocedure is developed for the sensitive detection of Pb2+ concentrations fro m 1 muM to 5 muM. the limit of detection by square-wave voltammetry after 2 0 s deposition time was found to be 0.1 muM and 1.0 muM with microwave acti vation and without microwave activation, respectively. Then, the Pb content in a water sediment sample detected by anodic stripping voltammetry at bor on-doped diamond electrodes is shown to be in good agreement with two other independent analytical procedures based on ICP mass spectroscopy and on so no-cathodic stripping voltammetry.