Fabrication of dopamine sensor based on a carbon paste electrode modified with tetracyanoquinodimethane and cobalt tungstate nanoparticles

This paper illustrated a precise, reliable, and sensitive electrochemical sensor for dopamine based on tetracyanoquinodimethane (TCNQ) and cobalt tungstate nanoparticles (CoWO4-NPs) modified carbon paste electrodes. The modified electrode was characterized by cyclic voltammetry (CV), differential pulse voltammetry, amperometry, and electrochemical impedance spectroscopy (EIS). The findings demonstrated significant electrocatalytic capability for dopamine sensing. The CV studies showed intensified electrocatalytic activity for dopamine oxidation by TCNQ@CoWO4/CPE due to a synergistic interaction between TCNQ and CoWO4 nanoparticles. The amperometric analysis resulted in a broader linear range of 2 µM to 80 µM for dopamine monitoring and a high sensitivity of 0.202 µA/µM. EIS analysis provided the lowest Rct value of 950 Ω cm2 for TCNQ@CoWO4/CPE compared to TCNQ/CPE, illustrating a high electron transfer capability. Besides this, TCNQ@CoWO4/CPE exhibited excellent stability, selectivity, and reproducibility. The modified sensor was found to be a useful tool for real-time sample analysis of commercially available dopamine injections.