scholarly journals Morphology–Dependent Electrochemical Sensing Properties of Iron Oxide–Graphene Oxide Nanohybrids for Dopamine and Uric Acid

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 835 ◽  
Author(s):  
Zhaotian Cai ◽  
Yabing Ye ◽  
Xuan Wan ◽  
Jun Liu ◽  
Shihui Yang ◽  
...  
Keyword(s):  
Uric Acid ◽  
Graphene Oxide ◽  
Iron Oxide ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Simultaneous Detection ◽  
Electrochemical Sensing ◽  
Electrochemical Performances ◽  
Hydrothermal Route ◽  
Sensing Properties

Various morphologies of iron oxide nanoparticles (Fe2O3 NPs), including cubic, thorhombic and discal shapes were synthesized by a facile meta-ion mediated hydrothermal route. To further improve the electrochemical sensing properties, discal Fe2O3 NPs with the highest electrocatalytic activity were coupled with graphene oxide (GO) nanosheets. The surface morphology, microstructures and electrochemical properties of the obtained Fe2O3 NPs and Fe2O3/GO nanohybrids were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. As expected, the electrochemical performances were found to be highly related to morphology. The discal Fe2O3 NPs coupled with GO showed remarkable electrocatalytic activity toward the oxidation of dopamine (DA) and uric acid (UA), due to their excellent synergistic effect. The electrochemical responses of both DA and UA were linear to their concentrations in the ranges of 0.02–10 μM and 10–100 μM, with very low limits of detection (LOD) of 3.2 nM and 2.5 nM for DA and UA, respectively. Moreover, the d-Fe2O3/GO nanohybrids showed good selectivity and reproducibility. The proposed d-Fe2O3/GO/GCE realized the simultaneous detection of DA and UA in human serum and urine samples with satisfactory recoveries.

scholarly journals Simultaneous Detection of Ascorbic Acid, Dopamine, and Uric Acid Using a Novel Electrochemical Sensor Based on Palladium Nanoparticles/Reduced Graphene Oxide Nanocomposite

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuyun Wei ◽  
Yangyang Liu ◽  
Zhifang Xu ◽  
Shenjun Wang ◽  
Bo Chen ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Palladium Nanoparticles ◽  
Electrochemical Impedance ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Fast Response ◽  
Electrochemical Performances ◽  
Glass Carbon Electrode ◽  
Glass Carbon

A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticles/reduced oxide nanocomposite-modified glass carbon electrode (PdNPs/rGO/GCE) was established in this study. Field emission scanning electron microscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGO/GCE), and the introduction of PdNPs has no effect on the morphology of rGO. Electrochemical impedance spectroscopy (EIS) studies revealed that the conductivity of PdNPs/rGO/GCE was higher than that of rGO/GCE and bare GCE. The electrochemical performances of PdNPs/rGO/GCE sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry using ascorbic acid (AA), dopamine (DA), and uric acid (UA) as analytes. At the optimized conditions, wide linear ranges of 0.5–3.5 mM (R2 = 0.99), 3–15 μM (R2 = 0.99) and 15–42 μM (R2 = 0.99), and 0.3–1.4 mM (R2 = 0.99) towards AA, DA, and UA in ternary mixture were observed, respectively. In addition to superior anti-interference capability, fast response (≤5 s), excellent reproducibility, and good long-term stability were also given by this sensor. These results suggested that PdNPs/rGO/GCE is promising for the simultaneous detection of AA, DA, and UA in practical application.

scholarly journals N-Doped Reduced Graphene Oxide/Gold Nanoparticles Composite as an Improved Sensing Platform for Simultaneous Detection of Dopamine, Ascorbic Acid, and Uric Acid

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4427
Author(s):  
Daria Minta ◽  
Zoraida González ◽  
Piotr Wiench ◽  
Stanisław Gryglewicz ◽  
Grażyna Gryglewicz
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Detection Limit ◽  
Electrochemical Performance ◽  
Reduced Graphene Oxide ◽  
Simultaneous Detection ◽  
Homogeneous Distribution ◽  
Reduced Graphene

Gold nanoparticles (AuNPs) were homogeneously electrodeposited on nitrogen-doped reduced graphene oxide (N-rGO) to modify a glassy carbon electrode (GCE/N-rGO-Au) in order to improve the simultaneous detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). N-rGO was prepared by the hydrothermal treatment of graphene oxide (GO) and urea at 180 °C for 12 h. AuNPs were subsequently electrodeposited onto the surface of GCE/N-rGO using 1 mM HAuCl4 solution. The morphology and chemical composition of the synthesized materials were characterized by field-emission scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical performance of the modified electrodes was investigated through cyclic voltammetry and differential pulse voltammetry measurements. Compared to GCE/rGO-Au, GCE/N-rGO-Au exhibited better electrochemical performance towards the simultaneous detection of the three analytes due to the more homogeneous distribution of the metallic nanoparticles as a result of more efficient anchoring on the N-doped areas of the graphene structure. The GCE/N-rGO-Au-based sensor operated in a wide linear range of DA (3–100 µM), AA (550–1500 µM), and UA (20–1000 µM) concentrations with a detection limit of 2.4, 58, and 8.7 µM, respectively, and exhibited satisfactory peak potential separation values of 0.34 V (AA-DA), 0.20 V, (DA-UA) and 0.54 V (AA-UA). Remarkably, GCE/N-rGO-Au showed a very low detection limit of 385 nM towards DA, not being susceptible to interference, and maintained 90% of its initial electrochemical signal after one month, indicating an excellent long-term stability.

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.

scholarly journals Molecular Mechanisms on the Selectivity Enhancement of Ascorbic Acid, Dopamine, and Uric Acid by Serine Oligomers Decoration on Graphene Oxide: A Molecular Dynamics Study

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2876
Author(s):  
Threrawee Sanglaow ◽  
Pattanan Oungkanitanon ◽  
Piyapong Asanithi ◽  
Thana Sutthibutpong
Keyword(s):  
Molecular Dynamics ◽  
Ascorbic Acid ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Hydrogen Bonds ◽  
In Silico ◽  
Molecular Mechanisms ◽  
Simultaneous Detection

The selectivity in the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) has been an open problem in the biosensing field. Many surface modification methods were carried out for glassy carbon electrodes (GCE), including the use of graphene oxide and amino acids as a selective layer. In this work, molecular dynamics (MD) simulations were performed to investigate the role of serine oligomers on the selectivity of the AA, DA, and UA analytes. Our models consisted of a graphene oxide (GO) sheet under a solvent environment. Serine tetramers were added into the simulation box and were adsorbed on the GO surface. Then, the adsorption of each analyte on the mixed surface was monitored from MD trajectories. It was found that the adsorption of AA was preferred by serine oligomers due to the largest number of hydrogen-bond forming functional groups of AA, causing a 10-fold increase of hydrogen bonds by the tetraserine adsorption layer. UA was the least preferred due to its highest aromaticity. Finally, the role of hydrogen bonds on the electron transfer selectivity of biosensors was discussed with some previous studies. AA radicals received electrons from serine through hydrogen bonds that promoted oxidation reaction and caused the negative shifts and separation of the oxidation potential in experiments, as DA and UA were less affected by serine. Agreement of the in vitro and in silico results could lead to other in silico designs of selective layers to detect other types of analyte molecules.

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