Microwave activation of electrochemical processes: Square-wave voltammetric stripping detection of cadmium in the presence of the surfactant triton X

A novel electrochemical cell based on a flow through system in a microwave cavity is shown to allow voltammetnc experiments under microwave conditions. Focusing of the microwave radiation at the electrode-solution (electrolyte) interface creates conditions of extreme localized heating with an inverted thermal gradient within the diffusion layer of the electrode and convective flow. The deposition and anodic stripping detection by square-wave voltammetry of Cd²⁺ in a 0.1 M acetate buffer solution is shown to be strongly enhanced by microwave activation. The temperature at the electrode-solution interface is calibrated with the reversible redox couple Ru(NH₃)₆^3+/2+ in 0.1 M acetate buffer. The effect of microwave activation on the square-wave voltammetric responses for the reduction of Ru(NH₃)₆^3÷ and for the detection of Cd^2÷ in 0.1 M acetate buffer solution are studied. In the presence of a nonionic surfactant, Triton X-100, which blocks the electrochemical Cd^2÷ response under conventional conditions, microwave activation is shown to have a considerable effect in enhancing the sensitivity for Cd²⁺ detection.