1986 Volume 2 Issue 6 Pages 511-516
By incorporating a quaternary ammonium salt-mediated extraction with electrochemical redox process, a membrane electrode which possesses "built-in" ability of extractive amplification of analyte concentrations in its liquid membrane was constructed. The built-in extraction electrode consists of a liquid membrane of tri-n-octylmethylammonium chloride on an immediate top of an underlying mercury film electrode. Detection of cadmium(II) at lower ppb levels in 1M potassium chloride solution was tested. Extractive accumulation of the analyte by a factor of 103 in the liquid membrane of the extraction electrode was achieved. Selectivity of the extraction electrode based on different extractability of each metal ion was demonstrated. The electrode was also characterized by chronoamperometry in terms of virtual thickness of diffusion layers.