DISCRIMINATION AMONG AMINO-ACIDS USING AN AMPEROMETRIC BIOSENSOR BASED ON ELECTROCHEMICAL NONLINEARITY

We propose a navel sensing system based on the multidimensional inform ation contained in a dynamic nonlinear response. A sinusoidal potentia l was applied to an amperometric L-amino acid sensor, and the resultin g current of the sensor was analyzed by fast Fourier transformation (F FT). The amplitudes of the higher harmonics of the FFT characterize th e nonlinear properties of the response. The amplitudes of the higher h armonics of the FFT exhibit characteristic changes which depend on the concentration and the chemical structure of amino acids at the sensor surface.