Electrochemical and quantum chemical studies of cetylpyridinium bromide modified carbon electrode interface for sensor applications

In this work, both electrochemical experiments and quantum chemical simulations were performed to explore an important topic namely the cetyl pyridinium bromide (CPB) modified carbon paste electrode (CPBMCPE) employed for detection of dopamine (DA) and uric acid (UA). The electrode was found to display excellent electrocatalysis and increased surface area for simultaneously detecting DA and UA via decreasing their oxidation overpotentials when compared to the bare electrode, demonstrating high selectivity and sensitivity. Although surfactants can increase carbon-electrode sensitivity for DA detection, its mechanism remains elusive. Here, we used quantum chemical models to tackle the interface at which sensing (electron transfer) takes place. Our computational results reveal that the charged cationic head of CPBs can offer an additional electron transfer site at the CPBMCPE interface such that the sensing ability of CPE is comparatively improved after the CPB modification. Such electrodes were also applied for sensing UA in a urine sample, reaching a satisfactory of recovery up to 98%. To comprehend, we also modeled the power of electron-accepting and donating of CPB with other commonly used cationic surfactants.