Design and development of a new hybrid spectroelectrochemical sensor. Annual technical progress report, September 15, 1996--September 14, 1997

'A new concept for a chemical sensor that demonstrates three modes of selectivity (electrochemistry, spectroscopy, and selective partitioning) is being developed. The spectroelectrochemical sensor consists of an optically transparent electrode (OTE) coated with a selective film. Sensing is based on the change in optical signal of light passing through the OTE that accompanies an electrochemical reaction of the analyte at the electrode surface. Thus, for an analyte to be detected, it must partition into the selective coating, be electrolyzed at the potential applied to the electrode, and either the analyte or its electrolysis product must absorb light at the wavelength chosen. Selectivity for the analyte relative to other solution components is obtained by choice of coating material, electrolysis potential, and wavelength for optical monitoring. The purpose of this new sensor is to significantly broaden the applicability of sensors to real samples by improving selectivity. This high level of selectivity is to be achieved without any fragile biocomponent. The concept is to be demonstrated with a sensor for ferrocyanide.