Preparation of a reduced graphene oxide/poly-l-glutathione nanocomposite for electrochemical detection of 4-aminophenol in orange juice samples

A novel electrochemical sensor, for the detection of 4-aminophenol (4-AP), was generated by electrodeposition of poly- l -glutathione (P- l -GSH) onto reduced graphene oxide (RGO) to form a RGO/P- l -GSH composite matrix on a glassy carbon electrode (RGO/P- l -GSH/GCE). The morphology and structure of the RGO/P- l -GSH modified GCE were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy and electrochemical impedance spectroscopy. As an electrochemical sensor, the RGO/P- l -GSH modified GCE composite exhibited strong catalytic activity toward the oxidation of 4-AP which was demonstrated by cyclic voltammetry (CV) and chronoamperometry. Furthermore, the electrochemical sensor exhibited an excellent current response for 4-AP over a wide linear range of 0.4 μM to 200 μM ( R 2 = 0.9934) with a lower detection limit (LOD) of 0.03 μM ( S / N = 3), as well as a sensitivity of 27.2 (μA μM −1 cm −2 ) and excellent selectivity, reproducibility and stability. The electrochemical sensor provides good anti-interference ability in the presence of glucose, fructose, paracetamol, ethanol, l -isoleucine, l -histidine, l -cysteine, dopamine, l -serine, l -tyrosine, phenylalanine, urea, hydrogen peroxide, K + , Ca 2+ , Na + , F − , Cu 2+ , Fe 3+ , Zn 2+ , SO 4 2− , SO 3 2− , Cl − , folic acid and ascorbic acid. The proposed electrochemical method was successfully applied to produce a sensor for the detection of 4-AP in juice and water samples. Schematic representation of the preparation of the RGO/P- l -GSH film.