Achieving direct electrochemistry of glucose oxidase by one step electrochemical reduction of graphene oxide and its use in glucose sensing

• A direct electron transfer reaction of glucose oxidase was observed on GCE/ERGO/SDS.
• This composite film was successfully applied in preparation of glucose biosensor.
• The detection limit of the biosensor was estimated to be 40.8 μM.
• The results from the sensor were similar to those obtained from the clinical analyzer.

In this paper, the direct electrochemistry of glucose oxidase (GOD) was accomplished at a glassy carbon electrode modified with electrochemically reduced graphene oxide/sodium dodecyl sulfate (GCE/ERGO/SDS). A pair of reversible peaks is exhibited on GCE/ERGO/SDS/GOD by cyclic voltammetry. The peak-to-peak potential separation of immobilized GOD is 28 mV in 0.1 M phosphate buffer solution (pH 7.0) with a scan rate of 50 mV/s. The average surface coverage is 2.62 × 10− 10 mol cm− 2. The resulting biosensor exhibited a good response to glucose with linear range from 1 to 8 mM (R2 = 0.9878), good reproducibility and detection limit of 40.8 μM. The results from the biosensor were similar (± 5%) to those obtained from the clinical analyzer.