Microwave activated voltammetry: The thermally enhanced anodic stripping detection of cadmium

In situ microwave activation of electrochemical processes in a novel electr ochemical cell, in which intense microwave radiation is focused locally int o the region at the electrode surface-solution interface, is shown to allow high-temperature voltammetry experiments at 100 mu m Pt disk electrodes. F actors such as the cell geometry and the deposition of a thin film of mercu ry are shown to influence the microwave effect. The detection of trace meta ls or impurities by anodic stripping voltammetry is a routinely applied pro cedure with applications especially in rapid online monitoring, in remote p lace analysis, or for extremely dilute samples. For cadmium detection by an odic stripping voltammetry microwave radiation is demonstrated to strongly affect the accumulation process but not the shipping process. Calibration o f the effects induced by microwave radiation on the experimentally observed voltammetric data, based on the equilibrium potentials for the Fe(CN)(6)(4 -/3-) and the RU(NH3)(6)(3+/2+) redox systems; demonstrates that the data o btained are consistent with a thermally enhanced process. The temperature a chievable at the electrode-solution interface before boiling and cavitation occurs, is shown to be strongly dependent on the type of electrode materia l and surface morphology. At a mercury film electrode deposited on platinum temperatures in excess of 150 degrees C can be applied in voltammetric exp eriments in a constant heating mode.