A novel microfabricated electrochemical sensor has been developed for the detection and measurement of heavy metal ions in aqueous media. The sensor consists of a silicon substrate, on which is fabricated an electrically interconnected, but diffusionally isolated, array of thin-film iridium microelectrodes upon which a thin film of mercury is electrodeposited. Square-wave anodic-stripping voltammetry is used for quantitative analysis. This method involves an initial preconcentration phase in which the array is held at a cathodic potential such that the metal ions are reduced and amalgamated into the mercury, followed by anodic stripping (re-oxidation) of the metal ions. The charge required to strip a given ionic species completely is proportional to its initial concentration in the test solution. Sensitivity in the parts per billion range has been demonstrated without the addition of supporting electrolytes, deoxygenation, agitation, or any other alterations to the water samples.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.