Functionalization of Arabic Gum by Both Oxidation and Acylation: Application as Sensing Materials for the Electrochemical Determination of Phenolic Compounds

Abstract

Novel functionalized Arabic gums (AGs) were obtained by oxidation and acylation reactions on raw Arabic gum. The synthesized materials were used as modifiers of carbon paste electrodes for the determination of quercetin (QCT), rutin (RUT) and both p-aminophenol (PAP) and acetaminophen (APAP) in 0.1 M phosphate buffer solution (PBS), pH 6.0. The identification of chemical functions on the surfaces of raw material was determined using Fourier transform infrared spectroscopy (FT-IR). Cyclic voltammetry and square wave voltammetry were used for the electrochemical study of QCT, RUT, PAP and APAP on modified electrodes. Electrochemical signals increased when the electrode was first modified with acylated gum in comparison to the unmodified electrode, and the signals became more important with the oxidized gum. Using oxidized AG modified carbon paste electrode (OAG-CPE), the linear range of the determination for both QCT and RUT was 0.020-0.090 mg/L, and from 1 to 9 mg/L for both PAP and APAP. Limits of detection were found to be 0.005, 0.023, 0.039 and 0.105 mg/L for QCT, RUT, PAP and APAP respectively. This sensor was first used for the direct quantification of APAP in commercialized tablets of Doliprane® 500 with a recovery of 94.3%, and secondly, for a simultaneous detection of both QCT and RUT in human urine.