Voltammetric Determination of Ascorbic Acid in the presence of Acetaminophen using a Carbon Paste Electrode Modified with Multiwall Carbon Nanotubes and 3-(4'-Amino-3'-Hydroxy-Biphenyl-4-yl)-Acrylic Acid

A carbon paste electrode (CPE) modified with 3-(4'-amino-3'-hydroxy-biphenyl-4-yl)-acrylic acid and multi-walled carbon nanotubes (MWCNTs), was prepared for simultaneous determination of ascorbic acid (AA) and acetaminophen (AC). The electrochemical response characteristics of the modified electrode toward AA and AC were investigated by cyclic voltammetry and square wave voltammetry (CV and SVW). The results showed an efficient catalytic role for the electro-oxidation of AA and AC, leading to a remarkable peak resolution (~320 mV) for two compounds. The mechanism of the modified electrode was analyzed by monitoring the CVs at various potential sweep rates and pHs of the buffer solutions. Under the optimum conditions, the calibration curve for AA was obtained in the range of 1.0×10-8-4.0×10-5 M. The proposed method was applied to determination of AA and AC in commercial drugs and in urine samples and the obtained results were satisfactory.