Numerical Simulation Based Accurate Models of Improved Chronoamperometry and Its Experimental Validation

Abstract

Based on the empirical formula for concentration change of a detected molecule on the surface of a electrode, an approximate mathematical model of improved chronoamperometry was established. The relationship between the working current and detection reagent concentration was analyzed qualitatively. Parameters for the electrode reaction and excitation potential were not included. To solve this problem, the Nernst equation and Fickʹs law were applied to construct an integral equation for the specific concentrations of the oxidant and reductant on the surface of the electrode. The current-time curve obtained numerically was used to investigate the relationship between the peak current and concentration of reagent, inertia time constant, standard potential of the reference electrode, initial value and steady state value of the voltage excitation. Using the improved chronoamperometry device, we studied the electrochemical behavior of K3(Fe(CN)6). The experimental results showed that the simulation results from the numerical model were much closer to the actual situation than the empirical model. The experimental results also confirmed the parameter relationships that were derived using the model. (Article)