Simultaneous electrochemical sensing of dopamine and uric acid with the aids of chemometric methods

It is important to simultaneously detect dopamine (DA) and uric acid (UA) for health monitoring and disease diagnostics. Studies shows that bimetallic catalysts with synergistic effect have a better catalytic performance in the simultaneous determination. Herein, a composite of N-doped CoFe on carbon matrix doped with Fe3O4 (CoFe/Fe3O4/NC) was prepared by pyrolyzing a metal-organic framework. Then the composite was modified on glassy carbon electrodes to simultaneously detect DA and UA. The study of double potential step chronoamperometry showed that the diffusion coefficients and the catalytic rate constants for UA were less than those of DA. Since the electrochemical signals related to DA and UA interfere with each other, the concentration calibration curve of one component would distort if the concentration of coexisting component varied. The simultaneous detection was executed via differential pulse voltammetry with the aid of chemometric methods. The models established by partial least squares regression analysis have little help for the simultaneous detection, especially for the concentration of UA in the samples. The models build by back propagation artificial neural network can realize the simultaneous determination with only 4 neurons in three-layer network. DA and UA in normal human serum were detected by the CoFe/Fe3O4/NC electrode with the aids of chemometrics.