Carboxylated graphene-alcohol oxidase thin films modified graphite electrode as an electrochemical sensor for electro-catalytic detection of ethanol

Abstract

A new enzyme-electrode is developed for the determination of ethanol by immobilizing carboxylated graphene (CG) and alcohol oxidase (AOX) on poly diallyldimethylammonium chloride (PDDA) modified graphite electrode (Gr). The biosensor showed high sensitivity and rapid detection of ethanol in the concentration range 250 μM to 1500 μM. Addition of ethanol reduced the reduction current of oxygen, which is due to the consumption of molecular oxygen for the oxidation of ethanol. The effect of temperature and pH on the performance of the biosensor has been studied. The excellent performance of the biosensor is attributed to large surface to volume ratio and high conductivity of graphene. This promotes direct electron transfer between redox enzymes and electrode surface. Low operating potential and specificity of the enzyme will restrict the interference of ascorbic acid, acetaminophen, and glucose. The biosensor was characterized by field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV) using Fe2+/Fe3+ as an electrochemical probe.

Keywords

• Alcohol Oxidase (AOX)
• Ethanol sensor
• Carboxylated Graphene (CG)
• Poly diallyldimethylammonium chloride (PDDA)