Gold nanoparticles-modified platinum (Au-NPs/Pt) microelectrode is used as a “probe”, and applied to detect Pb(II) in the presence of microwave irradiated-voltammetry synergetic system. Self-focusing of the microwave radiation creates a “hot spot” at the electrode/electrolyte interface within the diffusion layer of the electrode with an inverted thermal gradient and convective flow. The temperature at the electrode/solution interface is calibrated with reversible one electron redox system in aqueous K₂SO₄ solution (pH 3). The results indicate that the electrochemical performance at the Au-NPs/Pt microelectrode is significantly affected under the low microwave power. The Pb(II) stripping current at the (Au-NPs/Pt) microelectrode is shown to be strongly enhanced by microwave irradiated-voltammetry, which triggers approximately 10-times Pb(II) current response compared to those expected values in conventional conditions. The effect of surfactant, which blocks the electrochemical Pb(II) signal under conventional conditions, is remarkably reduced under the microwave radiation of voltammetry process.

Key words: microwave irradiation, voltammetry, “hot spot” effect, lead