An electrochemical dopamine sensor based on CoMn2O4/CQDs nanocomposite modified carbon paste electrode

CoMn2O4, carbon quantum dots (CQDs) and CoMn2O4/CQDs nanocomposites were successfully synthesized via a hydrothermal method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectrophotometry was employed to characterize its structure and morphology. An electrochemical sensor based on modification carbon paste electrode (CPE) using CoMn2O4/CQDs nanocomposites was developed for sensing dopamine (DA). It demonstrated excellent response ability and electrocatalytic activity for DA detection by cyclic voltammograms (CVs) and i-t plots. Experimental conditions such as CoMn2O4 to CQDs mass ratio, the pH of the electrolyte solution, scan rate, and instrumental parameters for i-t test was optimized. Under optimized conditions, CoMn2O4/CQDs/CPE (1:1) exhibited a remarkable linear relationship between the oxidation current and DA concentration across the ranges of 2.0-1000.0 mu M and 1000.0-60000.0 mu M in 0.1 M PBS. Additionally, the detection limit was as low as 0.0874 mu M. The sensor also expressed good selectivity, reproducibility, stability and recovery between 98.5 % and 104.2 % (RSD <5 %), thereby laying a robust foundation for future practical applications.