Amperometric detection of glucose using Prussian blue-graphene oxide modified platinum electrode

Abstract

An enzyme based biosensor was developed for the detection of glucose in blood plasma. The electrode was fabricated by immobilizing glucose oxidase (GOx) along with graphene oxide (GO) on Prussian blue (PB) modified platinum (Pt) electrode using nafion as a binder. The GO modification on Pt/PB electrode increases the voltammetric response current towards the reduction of H₂O₂ compared to Pt/PB electrode. The modified electrode showed a linear amperometric response at an applied potential of −0.1 V towards the detection of glucose from 2 μM to 20 μM with a detection limit of 1.35 μM and its sensitivity was found to be 175 × 10⁻² A M⁻¹ cm⁻². As the low applied potential avoids the interferences due to urea, uric acid and ascorbic acid, the amperometric response of the modified electrode was found to be negligible both in the presence and absence of glucose. The response time for 95% of the response current was found to be 5 s. The developed electrode shows excellent stability over a period of two weeks with only a 13.6% decrease from the initial amperometric response and an appreciable repeatability with relative standard deviation (RSD) of 4.43% (n = 6).