Graphene Oxide Modified Screen Printed Carbon Electrodes for Electrochemical Determination of Homocysteine using Catechol as Redox Mediator

Abstract

Graphene oxide (GO) was modified on the surface of screen printed carbon electrode (SPCE),whichis portable, inexpensive, and disposable, for the electrochemical detection of homocysteine (Hcy)via 1,4-Michael addition reaction using catechol (CA) as redox mediator. Typically, CAwas first oxidized to its corresponding ortho-quinone which could subsequently undergo a 1,4-Michael addition, forming a new electrochemically active species thatcould further get oxidized and reduced.This new reduction peak could be clearly observedat ca.-0.27V vs. Ag/AgClby differential pulse voltammetry (DPV).Under the optimized conditions, this new reduction peak increased linearly with Hcy concentrationsin the range of 15-150 µM, and the limit of detection (LOD) was found to be 12 µM, literally lower than the concentration of Hcy in human plasmarelated to a high risk of cardiovascular diseases (CVDs).Therefore, the developed electrochemical method for Hcy detection could potentially be applied in medical applications.