ARMAX Modeling and Impedance Analysis of Voltammetric E-Tongue for Evaluation of Infused Tea

This paper presents a modeling technique to analyze the performance of the electrodes of a custom made voltammetric e-tongue. In this methodology, autoregressive moving average models are estimated for five working electrodes of the e-tongue made of different noble metals in classifying three different classes of infused tea. The experimental input-output responses of the electrodes are used for modeling. The model transfer functions are fitted to an equivalent circuit from which the circuit impedances and electrical parameters are derived. We propose that there is a transition frequency at which values of the electrical parameters shift from positive to negative. The performance of the electrodes is analyzed in terms of data consistency, stability, and formation of negative parameters. Therefore, the proposed modeling technique can be used for selecting the electrodes and the operating frequency to improve the performance of the e-tongue.