A β-cyclodextrin(β-CD)/graphene based electrode was fabricated by a simple one-step electropolymerization of β-CD and reduced graphene oxide (rGO) on the GCE. The proposed electrode showed remarkable enhancement effects on the oxidation current of sulphasalazine (SSLZ) and 5-aminosalicylic acid (5-ASA). The reduced graphene oxide is helpful for enhancing conductivity of electrode, efficient attaching β-CD to the electrode and loading more number of β-CD which is beneficial for the affinity function of β-CD. The modified electrode was well characterized by field-emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The effect of the pH, supporting electrolyte, accumulation time and voltammetry parameters were fully investigated and optimum conditions were established. Under the optimum conditions, the modified electrode exhibited linearity proportional to 5-ASA and SSLZ concentration in the range of 0.04–13.0 μM and 0.2–12.0 μM, with a limit of detection (LOD) down to 8.8 nM and 0.05 μM for 5-ASA and SSLZ, respectively. The modified electrode showed excellent sensitivity, selectivity and remarkable reproducibility. Finally, the developed method for detecting SSLZ and 5-ASA was successfully applied in human serum samples.
