New chemically modified electrode obtained from the interaction of the biosurfactant saponin from Glycyrrhiza glabra with graphene oxide matrix

Abstract

Abstract This work aimed by employing cyclic voltammetry and Fourier transform infrared spectroscopy (FTIR) to study the interactions of the biosurfactant saponin glycyrrhizin (SAP) with graphene oxide (GO) to the development of hybrid nanomaterials. Chemically Modified Electrodes (CMEs) based on carbon paste were developed. First, the electrochemical behavior of GO on the surface of the carbon paste electrode (CPE) was studied, resulting in the CME called (CPE/GO), this system showed good electrochemical characteristics such as: formal potential (Eo) of 300 mV, separation peak (DE) of 170 mV vs Ag/AgCl operating in 0.5 mol/L KCl solution and applied potential sweep speed of 20 mV vs Ag/AgCl. The second CME called carbon paste electrode modified with saponin (CPE/SAP) presented a formal potential (Eo) of 250 mV, peak separation (DE) of 100 mV vs Ag/AgCl operating under the same conditions as above. Finally, the carbon-based CME containing SAP associated with graphene oxide was named (CPE/GO/SAP). This system presented excellent characteristics when operated under the same conditions, with a current gain of 1.74 and 2.16 times greater compared to CPE/GO and CPE/SAP respectively. High stability of SAP was also observed when associated with GO in the carbon paste matrix, maintaining a high response rate, with a drop of only 2% of current after 5 hours, evidencing a favorable interaction and resulting in a hybrid nanomatrix with improvements in the redox process. FTIR spectroscopy also showed that there is a positive interaction of SAP when associated with GO, promoted from functional groups present in both systems.