Analytical Utility of the Iridium-Based Mercury Ultramicroelectrode with Square-Wave Anodic Stripping Voltammetry

The characterktics of the irldium-based hemkphwkai mercury uitramlcrodectrode (Ha-UME) in conjunction with squarewave anodic stripping voltammetry (SWASV) have been Investigated. Udng Hg-UMEs of 5-10-pn~ radii, samples were analyzed without any added electrolyte, deoxygenatlon, or forced convectlon. The peak stripping currents displayed a linear rdation8hip with d.porltion times varying from 1 to 1200 8. Peak potentlais and current remained substantlaily unchanged with electrolyte concentrations of 1-104 M. The reproduclblilty and useful lifetime of the Hg-UME was studied and found to be excellent over several days use. The application of SWASV theory for mercury film electrodes is shown to not entirely describe the rerpow at the Hg-UME, especially at low square-wave frequencies.