Ionic Liquid Functionalized Graphene-Based Electrochemical Biosensor for Simultaneous Determination of Dopamine and Uric Acid in the Presence of Ascorbic Acid

An electrochemical biosensor for the simultaneous determination of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) was developed using a glassy carbon electrode modified with 1-butyl-3-methylimidazolium 2-amino-3-mercaptopropionic acid salt ionic liquid functionalized graphene (IL-G/GCE). The IL-G/GCE possessed excellent electrocatalytic activity toward the oxidation of AA, DA and UA. The separations of oxidation peak potentials of AA-DA, DA-UA, and AA-UA were 147, 145 and 292 mV, respectively. The electrochemical sensor showed excellent selectivity and stability and was applied successfully to the determination of DA and UA in real urine samples using the standard addition method with recoveries of 97.0-103.8%.