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An equivalent circuit, which extends the Randles model to include coupled chemical steps, is considered for a finite diffusion layer, describing synthetic metals. Information was used, concerning the effect of interaction of solution species on the layer circuit, together with complimentary kinetic parameters froim a nonlinear least squares fit to the dispersion data, of two-dimensional model functions, to study the glucose induced response of polyaniline and NMP.TCNQ in glucose oxidase loaded synthetic metals.

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The amperometric biosensor has become a convenient analytical device concept since the biorecognition element can be highly specific to the analyte of interest when coupled to the appropriate transducer. However, a shortcoming of this system is that the transducer alone is not necessarily specific to the analyte, but only in conjunction with the recognition element. Since many applications require that the sensor be used in complex analytical media, other sample species may cause a direct response at the transducer, for example electroactive species may be directly oxidized or reduced at an electrode in an electrochemical sensor, yielding an erroneous signal. Filtration/membrane barriers have been proposed to overcome this, but this also eliminates any information about the interferent. In this article the role of impedence spectroscopy is examined as a technique to probe overlapping electrochemical signals by separation in the frequency domain. Hydrogen peroxide is examined as a model to test the feasibility of extraction of quantitative data in this control mode, and experimental conditions are determined where analytical data may be obtained to extract the peroxide signal from other electrochemical information in an enzyme biosensor based on peroxide determination.

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