Electrochemical Analysis of Caffeine at the Electrode Modified by Functionalized Graphene Oxide with Alizarin Red

In this study, reduced graphene oxide (RGO) was first synthesized and then it was reacted by alizarin red S (ARS) and therefore RGO functionalized with ARS was prepared (ARS/RGO). Then, structural analysis of the manufactured material was done by SEM and FTIR techniques. The FTIR results were confirm the interaction between ARS and RGO and the formation of ARS/RGO. A new electrochemical sensor was fabricated on the surface of a glassy carbon electrode modified with ARS/RGO. The prepared electrode showed a quasi-reversible electrochemical behavior and also had a significant effect on the electrocatalytic oxidation of caffeine (CAF). The modified electrode was able to measurement the CAF as an electrochemical sensor. The effect of different parameters was investigated on the oxidation of CAF at the modified electrode; the sensor has the highest current at pH= 4.0. The effect of different interference species on the response of CAF, and also the reproducibility and repeatability of the sensor was investigated and acceptable results were obtained. The electrochemical determination of CAF on the electrode surface was investigated by differential pulse voltammetry and in the linear range of 1.0-100.0 µM, the detection limit value was obtained as 0.022 µM. Finally, the designed sensor was used to measure the amount of CAF in some real samples and satisfactory results were obtained.