Electroanalysis of Ascorbic Acid in Fresh Orange Juice Using a PTH/MWCNTCOOH-RGO/CS/CuO Film Modified Carbon Paste Electrode

Abstract

The incorporation, characterization, and analytical ability of an ascorbic acid (AA) voltammetric sensor, based on the PTH/MWCNTCOOH-RGO/CS/CuO modified carbon paste electrode (CPE), were studied. The nanocomposite was prepared via an in situ chemical polymerization route. The structural characterization, surface morphology, and thermal analysis of the modified polymers were confirmed. The kinetics and mechanism of the oxidation process of AA on the modified electrode were studied via scan rate analysis. The quantitative detection of AA was achieved effectually by a square wave voltammetry (SWV) technique. The proposed voltammetric sensor exhibited high performance in 0.1 M phosphate-buffered solution (PBS) at pH 3. In the pH range 3 to 7 AA undergoes irreversible oxidation via transfer of 2H+/2e-. The proposed sensor showed a wide linear range (5 µM to 2 mM) and a low detection limit (0.613 µM). Additionally, the reproducibility and stability (at the 1 mM level) expressed in terms of relative standard deviation (RSD) was 2.13% and 1.98% respectively. The practicality of the proposed sensor was confirmed by the successful detection of ascorbic acid in fresh orange juice and the recovery was between 107.9% and 92.63%, with excellent accuracy.

Electrocatalytic Activity Enhancement Using Graphene-Metal Oxide Nanocomposites for the Ultra Low Level Detection of Biomolecules

“…11,12 RGO metal oxide-based catalyst was also used for the detection of ascorbic acid (AA), epinephrine (EPN), uric acid (UA), and tyrosine (TYR). 13,14 Large number of work also progresses in the applications of gas sensing, reduction of toxic metals, antibacterial materials and drug delivery etc., using different MO/RGO composites such as Co 3 O 4 /RGO, NiO/RGO, CdO/RGO, and Fe 3 O 4 /RGO. [15][16][17][18] Nowadays, the electrochemical sensors based on metal oxide reduced graphene oxide (MO/RGO) nanocomposite have gained worldwide interest in research for the sensitive and selective detection of biomolecules.…”

Electrochemical Immunoassay of Melanoma Biomarker CPEB4 Based on Cobalt Porphyrin Functionalized Graphene Oxide

“…[13][14][15] However, these sensors often be limited their application in biology due to biotoxicity, limited surface functionality, or susceptibility to non-specific binding. [16][17][18][19] To improve the detection performance of the sensors and to enable signal amplification, some nanomaterials with unique biological functions and physicochemical properties, such as graphene oxide (GO), [20][21][22][23] gold nanoparticles (AuNPs) 24,25 and two-dimensionalmetal-organic framework (2D-MOF) nanoenzymes [26][27][28] have been used as carriers for immunosensors.…”