Electrochemical processes are an effective method for detecting dangerous food ingredients. The synergistic between the reduction-oxidation (redox) processes inspired several papers and spurred research towards studying the new materials that can further adapt to optimize the rapid detection of chemical compounds. In this study, we report the eco-synthesis using graphene/TiO2 rutile (G/TiO2) electrode microstructures easily prepared through the physical method by mixing graphene and TiO2 powder and its application for sensing L-tryptophan (Trp) compound. The material characterization results show that the graphene surface is smoother than the G/TiO2 material. Graphene has been detected using X-ray diffraction (XRD) at a value of 2 thetas 26.39° and TiO2 forms rutile crystals (110). The FTIR spectrum exhibits the functional groups from graphene of -OH, C-H, C=C, C-O, and TiO2 identified with Ti-O bonds. The electrochemical test against G/TiO2 electrode microstructures for Trp compound shows that 0.5 g TiO2 rutile was the best composition functionalized with graphene material under 0.1M K3[Fe(CN)6] + 0.1M NaNO3 electrolyte with a scan rate of 0.1 V/s. Determination of the detection limit was obtained at 0.005 mg/L with a HorRat value of 1.05%. The stability test was carried out for 25 days, and the addition of Pb(NO3)2 as an interference compound had a significant effect on the decrease in electrode performance.
Keywords: TiO2; electrochemical; graphene; sensor; tryptophan.