scholarly journals Simultaneous Voltammetric Determination of Ascorbic Acid, Paracetamol, and Caffeine Using Electrochemically Reduced Graphene-Oxide-Modified Electrode

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Nguyen Hai Phong ◽  
Tran Thanh Tam Toan ◽  
Mai Xuan Tinh ◽  
Tran Ngoc Tuyen ◽  
Tran Xuan Mau ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Anodic Stripping Voltammetry ◽  
Pharmaceutical Preparations ◽  
Differential Pulse ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

In the present paper, graphene oxide was directly electrodeposited by means of cyclic voltammetric techniques on the glassy-carbon electrode (GCE) to obtain a reduced graphene-oxide-modified electrode (ErGO/GCE). Cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DP-ASV) had been utilized to study the electrochemical behavior of ErGO/GCE toward ascorbic acid (AA), paracetamol (PA), and caffeine (CA). Differential pulse voltammetry results show that AA, PA, and CA could be detected selectively and sensitively on ErGO/GCE with peak-to-peak separation of 312 mV and 756 mV for AA–PA and PA–CA, respectively. The factors affecting the voltammetric signals such as pH, scan rate, and interferents were addressed. The results reveal that the ErGO/GCE-modified electrode exhibits excellent electrochemical activity in the oxidation of PA, CA, and AA. The detection limits are 0.36 μM, 0.25 μM, and 0.23 μM for AA, PA and CA, respectively, suggesting that the ErGO/GCE can be utilized with high sensitivity and selectivity for the simultaneous determination of these compounds. Finally, the proposed method was successfully used to determine AA, PA, and CA in pharmaceutical preparations.

scholarly journals Simultaneous Determination of Uric Acid and Xanthine Using a Poly(Methylene Blue) and Electrochemically Reduced Graphene Oxide Composite Film Modified Electrode

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Gen Liu ◽  
Wei Ma ◽  
Yan Luo ◽  
Deng-ming Sun ◽  
Shuang Shao
Keyword(s):  
Methylene Blue ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Composite Film ◽  
Simultaneous Determination ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were3.00×10-8 M and5.00×10-8 M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity.

scholarly journals A label-free biosensor based on graphene and reduced graphene oxide dual-layer for electrochemical determination of beta-amyloid biomarkers

2020 ◽  
Vol 187 (5) ◽  
Author(s):  
Jagriti Sethi ◽  
Michiel Van Bulck ◽  
Ahmed Suhail ◽  
Mina Safarzadeh ◽  
Ana Perez-Castillo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Label Free ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

AbstractA label-free biosensor is developed for the determination of plasma-based Aβ1–42 biomarker in Alzheimer’s disease (AD). The platform is based on highly conductive dual-layer of graphene and electrochemically reduced graphene oxide (rGO). The modification of dual-layer with 1-pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS) is achieved to facilitate immobilization of H31L21 antibody. The effect of these modifications were studied with morphological, spectral and electrochemical techniques. The response of the biosensor was evaluated using differential pulse voltammetry (DPV). The data was acquired at a working potential of ~ 180 mV and a scan rate of 50 mV s−1. A low limit of detection (LOD) of 2.398 pM is achieved over a wide linear range from 11 pM to 55 nM. The biosensor exhibits excellent specificity over Aβ1–40 and ApoE ε4 interfering species. Thus, it provides a viable tool for electrochemical determination of Aβ1–42. Spiked human and mice plasmas were used for the successful validation of the sensing platform in bio-fluidic samples. The results obtained from mice plasma analysis concurred with the immunohistochemistry (IHC) and magnetic resonance imaging (MRI) data obtained from brain analysis.

scholarly journals SIMULTANEOUS ELECTROCHEMICAL DETECTION OF ASCORBIC ACID, DOPAMINE, AND URIC ACID AT MAGNETIC NANOPARTICLES/REDUCED GRAPHENE OXIDE MODIFIED ELECTRODE

2021 ◽  
Vol 83 (3) ◽  
pp. 85-92
Author(s):  
Azleen Rashidah Mohd Rosli ◽  
Farhanini Yusoff ◽  
Saw Hong Loh ◽  
Hanis Mohd Yusoff ◽  
Muhammad Mahadi Abdul Jamil ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Magnetic Nanoparticles ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Reduced Graphene

A magnetic nanoparticles/reduced graphene oxide modified glassy carbon electrode (MNP/rGO/GCE) was fabricated via one-step facile synthesis route for the simultaneous determination of ascorbic acid (AA), dopamine (DA), along with uric acid (UA). A series of diseases and disorders has been associated with irregular levels of these respective analytes, thus early detection is highly crucial. Physical and electrochemical characterization of the modified electrode was conducted by using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) analysis, X-Ray Diffraction (XRD) analysis and Brauneur-Emmet-Teller (BET), Cyclic Voltammetry (CV) and Electron Impedance Spectroscopy (EIS). The results obtained confirmed the formation of MNP/rGO composite. Differential pulse voltammetry (DPV) of MNP/rGO/GCE displays three well-defined peaks which associated to AA, DA and UA, respectively. The response towards DA is linear in the concentration range of 15 nM to 100 µM with a detection limit of 0.19 nM while a response to AA and UA is also linear in the concentration range of 10 µM to 100 µM with a limit of detection 0.22 µM and 45 nM respectively. The proposed modified electrode offers a good response towards simultaneous detection of three different electroactive species with excellent electron transfer rate, great capacitance and ideal diffusive control behavior.

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