Direct electrochemical non-enzymatic assay of glucose using functionalized graphene

A non-enzymatic amperometric sensor is developed based on the graphite electrode modified with functionalized graphene for the determination of beta, d (+)-glucose. Cyclic voltammetry and electrochemical impedance spectroscopy techniques are used to study the behavior. Atomic force microscopy was used to study the surface topography of the working electrode before and after its modification. The sensor enabled the direct electrochemical oxidation of beta, d (+)-glucose in alkaline medium and responded linearly to the analyte over the range from 0.5 x 10(-3) to 7.5 x 10(-3) M with a limit of detection of 10 mu M. The sensor is found to exhibit a better sensitivity of 28.4 mu A mM(-1) cm(-2), good stability, and shelf life. The sensitivity of the sensor to beta, d (+)-glucose was not affected by the commonly co-existing interfering substances such as l-ascorbic acid, dopamine, uric acid, and acetaminophen.