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

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Résumé

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.

Mots-clés

gum arabic, oxidation, acylation, electrochemical sensor, phenolic compounds, electrochemical determination