Unveiling the Fundamental Mechanisms of Graphene Oxide Selectivity on the Ascorbic Acid, Dopamine, and Uric Acid by Density Functional Theory Calculations and Charge Population Analysis

The selectivity of electrochemical sensors to ascorbic acid (AA), dopamine (DA), and uric (UA) remains an open challenge in the field biosensing. In this study, selective mechanisms for detecting AA, DA, UA molecules on graphene oxide substrates were illustrated through charge population analysis from density functional theory (DFT) calculation results. Our substrate models contained 1:10 oxygen per carbon ratio reduced oxide, functionalized configurations selected according formation energy. Geometry optimizations performed pristine graphene, epoxy-functionalized hydroxyl-functionalized at DFT level with vdW-DF2 corrections. From calculations, AA was bound both epoxy GO relatively low adsorption energy, while DA adsorbed stronger electronegative groups. strongest groups corresponded largest amount electron transfer pi orbitals. Local loss created local electric fields that opposed during oxidation reaction. agreed results previous experimental studies provided insight into other electrode modifications sensing.