Low potential determination of dopamine in the presence of ascorbic acid using phenothiazine dye-functionalized graphite oxide-modified electrode

Azure A, a phenothiazine dye was functionalized at graphite oxide through EDC/NHS coupling chemistry. The Azure A-functionalized graphite oxide (AzA-GO) was modified at paraffin impregnated graphite electrode (PIGE) and was used in the precise electrochemical determination of dopamine (DA) in the presence of ascorbic acid (AA). The functionalized AzA-GO was characterized using FTIR, UV-visible spectroscopy, and scanning electron microscopy (SEM). The AzA-GO-modified electrode was characterized by cyclic voltammetry (CV). The electrocatalytic oxidation of DA was found to happen at a low oxidation potential of 0.14 V by the modified electrode. The determination of DA was linear in the concentration range of 8.6 x 10-6 to 9.09 x 10-3 M with the detection limit of 7.2 x 10-7 M. The selective determination of DA in the presence of 100 times higher concentration of AA was achieved by differential pulse voltammetry (DPV). The modified electrode offered a simple, sensitive, and selective determination of low levels of DA at the lower oxidation potential. The proposed sensor has the advantage of easy fabrication, low cost, good sensitivity, selectivity, reproducibility, and stability.

Automated summary

In this study, the precise electrochemical determination of dopamine was achieved by modifying a graphite electrode. The modified electrode allowed for the selective determination of dopamine at low concentrations at a lower oxidation potential, and demonstrated advantages such as simple fabrication, low cost, high sensitivity, good selectivity, reproducibility, and stability.