Graphene Paste Electrode Modified with Sodium Dodecyl Sulfate Surfactant for the Determination of Dopamine, Ascorbic Acid and Uric Acid

Sodium dodecyl sulfate surfactant modified graphene paste electrode (SDSMGPE), prepared by electrochemical immobilization of the Sodium dodecyl sulfate surfactant (SDS) on a graphene paste electrode, was applied for simultaneous determination of dopamine (DA) in the existence of ascorbic acid (AA) and uric acid (UA) through cyclic voltammetry(CV) and differential voltammetry(DPV). The modified electrode shows strong electrocatalytic function for the oxidation of DA, AA and UA and three well-defined voltammetric peaks of about 167 mV, 12 mV and 303 mV by CV method. A linear response in the range of (1×10-5)-(1×10-3) M with a detection limit of 4.7×10-6 M and limit of quantification limit 15×10-6 M for DA was obtained. This SDSMGPE indicated a potent and persistent electron mediating behavior bring up by adequately separated oxidation peaks of DA, AA and UA. The bare graphene paste electrode (BGPE) and SDSMGPE were characterized using Energy-dispersive X-ray spectroscopy (EDX) and Field emission scanning electron microscopy (FESEM) were used to check the electrochemical efficiency of electrodes. The effects of graphene paste constitution, concentration, surfactant, pH, and scan rate were investigated. The modified electrode is highly stable and can be used to the determination of DA in injection samples. The proposed method is simple, fast, sensitive, selective, stable, reproducible and accurate.