Oxide Modified Glassy Carbon Electrode Research Articles

Elucidation of DNA-Eltrombopag Binding: Electrochemical, Spectroscopic and Molecular Docking Techniques.

Eltrombopag is a powerful adjuvant anticancer drug used in treating MS (myelodysplastic syndrome) and AML (acute myeloid leukemia) diseases. In this study, the interaction mechanism between eltrombopag and DNA was studied by voltammetry, spectroscopic techniques, and viscosity measurements. We developed a DNA-based biosensor and nano-biosensor using reduced graphene oxide-modified glassy carbon electrode to detect DNA-eltrombopag binding. The reduction of desoxyguanosine (dGuo) and desoxyadenosine (dAdo) oxidation signals in the presence of the drug demonstrated that a strong interaction could be established between the eltrombopag and dsDNA. The eltrombopag-DNA interaction was further investigated by UV absorption and fluorescence emission spectroscopy to gain more quantitative insight on binding. Viscosity measurements were utilized to characterize the binding mode of the drug. To shed light on the noncovalent interactions and binding mechanism of eltrombopag molecular docking and molecular dynamics (MD), simulations were performed. Through simultaneously carried out experimental and in silico studies, it was established that the eltrombopag binds onto the DNA via intercalation.

An ultrasensitive electrochemical sensor for detecting porcine epidemic diarrhea virus based on a Prussian blue-reduced graphene oxide modified glassy carbon electrode

This study developed a novel, ultrasensitive sandwich-type electrochemical immunosensor for detecting the porcine epidemic diarrhea virus (PEDV). By electrochemical co-deposition of graphene and Prussian blue, a Prussian blue-reduced graphene oxide-modified glassy carbon electrode was made, further modified with PEDV-monoclonal antibodies (mAbs) to create a new PEDV immunosensor using the double antibody sandwich technique. The electrochemical characteristics of several modified electrodes were investigated using cyclic voltammetry (CV). We optimized the pH levels and scan rate. Additionally, we examined specificity, reproducibility, repeatability, accuracy, and stability. The study indicates that the immunosensor has good performance in the concentration range of 1 × 101.88 to 1 × 105.38 TCID50/mL of PEDV, with a detection limit of 1 × 101.93 TCID50/mL at a signal-to-noise ratio of 3σ. The composite membranes produced via co-deposition of graphene and Prussian blue effectively increased electron transport to the glassy carbon electrode, boosted response signals, and increased the sensitivity, specificity, and stability of the immunosensor. The immunosensor could accurately detect PEDV, with results comparable to real-time quantitative PCR. This technique was applied to PEDV detection and served as a model for developing additional immunosensors for detecting hazardous chemicals and pathogenic microbes.

Simultaneous Quantitation of Lead and Cadmium on an EDTA-Reduced Graphene Oxide-Modified Glassy Carbon Electrode.

Cadmium (Cd) and lead (Pb) are classified as category one toxicants. The provisional guideline values, according to the World Health Organization (WHO), for Cd and Pb are 3 and 10 ppb, respectively. An easy, quick, and cheap analytical technique is in demand for the determination of these toxic heavy metals in water. Hence, a novel electrochemical sensing platform is developed by modifying the glassy carbon electrode with ethylenediaminetetraacetic acid (EDTA)-functionalized reduced graphene oxide (ErGO) for the low-cost simultaneous quantitation of toxic heavy-metal ions, lead and cadmium, in real water samples. EDTA is grafted to the surface of graphene oxide, via amine linkage, and the oxygen functionality is reduced by a green agent, tyrosine. Various physical and electrochemical characterizations of the as-prepared electrocatalytic material were performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), ζ-potential, ultraviolet diffuse reflectance spectroscopy (UV-DRS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), etc. The glassy carbon electrode (GCE) is modified with ErGO by a simple drop-casting method for simultaneous metal-ion quantitation by differential pulse voltammetry (DPV). EDTA functionalization of graphene oxide and its further reduction using the green agent enhance the stability and sensitivity of the electrode substrate. The limits of detection for cadmium and lead ions calculated for ErGO/GCE are 1.02 and 2.52 ppb, while the limits of quantification for lead and cadmium ions are 3.41 and 8.4 ppb, and their sensitivities are 0.8 and 0.6 nA/ppb, respectively. Real river water contains 200.2 ± 0.38 ppb of Pb2+ ions (mean ± stdev, n = 3) by the DPV technique, which is validated by ICP-OES analysis.

Fabrication of Sulfur-Doped Reduced Graphene Oxide Modified Glassy Carbon Electrode (S@rGO/GCE) Based Acetaminophen Sensor

In the past few years, the design and fabrication of highly sensitive and selective electrochemical sensors have received enormous attention from electrochemists. Acetaminophen is an important drug that is used as an antipyretic and analgesic drug throughout the world. It is important to monitor the accurate amount of acetaminophen. Herein, we have prepared sulfur-doped reduced graphene oxide (S@rGO) using simple strategies. The morphological feature of the S@rGO was characterized by using scanning electron microscopy whereas phase purity and formation of S@rGO were authenticated by X-ray diffraction. Further, the glassy carbon electrode was modified using S@rGO as an electrode modifier and employed as an acetaminophen sensor (S@rGO/GCE). This modified sensor (S@rGO/GCE) demonstrates a reasonable detection limit of 0.07 µM and a sensitivity of 0.957 µA/µMcm2.

One-step Electrodeposition of CuNi Bimetallic Nanocatalyst Anchored on Reduced Graphene Oxide Modified Glassy Carbon Electrode for Nonenzymatic Sensing of Glucose

One-step Electrodeposition of CuNi Bimetallic Nanocatalyst Anchored on Reduced Graphene Oxide Modified Glassy Carbon Electrode for Nonenzymatic Sensing of Glucose

Novel Electrochemical Sensor for the Determination of Bisphenol A Using a Molybdenum(IV) Sulfide Quantum Dots Polysodium Styrene Sulfonate Functionalized Reduced Graphene Oxide Modified Glassy Carbon Electrode (GCE) by Differential Pulse Voltammetry (DPV)

A sensitive electrochemical platform for the determination of bisphenol A (BPA) was constructed. A hybrid of MoS2 quantum dots decorated poly sodium styrene sulfonate functionalized reduced graphene oxide (MoS2 QDS@PSS-rGO) was prepared by a simple method. The hybrid was cast on a bare glassy carbon electrode (GCE) to form the MoS2 QDs@PSS-rGO/GCE. The electrochemical response of BPA on the MoS2 QDs@PSS-rGO/GCE was significantly enhanced compared to the unmodified electrode, indicating that the nanocomposite possessed an electrocatalytic effect. A novel method was established to determine BPA with a detection limit of 0.008 μM. The applicability of the prepared sensor was demonstrated to determine BPA in real samples with high recoveries.

Electrochemical Dopamine Sensor Based on Gold Nanoparticles Electrodeposited on a Polymer/Reduced Graphene Oxide-Modified Glassy Carbon Electrode

A novel electrochemical dopamine (DA) sensor based on Au nanoparticles (AuNPs) electrochemically loaded on poly([2,2′;5′,2″]-terthiophene-3′-carbaldehyde)/reduced graphene oxide (poly(TTP)/rGO) improved glassy carbon electrode (GCE) was fabricated. The Au@poly(TTP)/rGO/GCE was evaluated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), amperometry, and electrochemical impedance spectroscopy (EIS). The optimized Au@poly(TTP)/rGO/GCE sensor had a wide electroactive surface area and exhibited good selectivity. The linear determination range of the sensor was from 0.02 to 232 µM with a sensitivity of 315 µA/mM/cm2. The limit of detection (LOD) was estimated to be 11.5 nM using signal-to-noise (S/N) ratio of 3. Additionally, the sensor displayed excellent selectivity, satisfactory response time from 4.5 to 6 s, replicability with a relative standard deviation (RSD) of 2.31%, reproducibility with a RSD of 3.67%, and storage stability with 92.57% of its initial current response for 37 days. The Au@poly(TTP)/rGO/GCE was employed to estimate DA in injection samples.

Electrochemical Determination of Diclofenac Sodium in Pharmaceutical Sample Using Copper Nanoparticles/Reduced Graphene Oxide Modified Glassy Carbon Electrode

Electrochemical Determination of Diclofenac Sodium in Pharmaceutical Sample Using Copper Nanoparticles/Reduced Graphene Oxide Modified Glassy Carbon Electrode

Simultaneous determination of catechol and hydroquinone with L-cysteine and nickel cobaltite Co-Functionalised Graphene Oxide Modified Glassy Carbon Electrode

ABSTRACT Catechol and Hydroquinone are considered to be main organic pollutants in water, and have a threat to human health and ecology security. It is imperative to establish a detection method of catechol and hydroquinone with high selectivity and sensitivity.In this work, a composite of L-Cysteine and nickel cobaltite co-functionalised graphene oxide was synthesised successfully by a facile hydrothermalmethod.The morphology and structure of the as-prepared composite was characterised by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The results revealed that the final product formed a 3D framework with urchin-like nickel cobaltite nanoparticle tightly packed on the layers of graphene oxide. The electrochemical properties of the composite modified glassy carbon electrode for detecting hydroxybenzeneisomers (hydroquinone and catechol) were tested by cyclic voltammetry and differential pulse voltammetry. The results discovered that the modified electrode exhibited an excellent repeatability and anti-interference towards the detection of catechol and hydroquinonewith linear response in the range of 10–140 μM and 10–200 μM, respectively.

Simple and Rapid Determination of Tartrazine Using Poly(l-arginine)/Electrochemically Reduced Graphene Oxide Modified Glassy Carbon Electrode

Simple and Rapid Determination of Tartrazine Using Poly(l-arginine)/Electrochemically Reduced Graphene Oxide Modified Glassy Carbon Electrode

Preparation of Eosin Y/Graphene Oxide Modified Glassy Carbon Electrode as a Sensing Platform for Dopamine and Epinephrine Detection

Preparation of Eosin Y/Graphene Oxide Modified Glassy Carbon Electrode as a Sensing Platform for Dopamine and Epinephrine Detection

Electrochemical Determination of Hydrogen Peroxide by a Nonenzymatic Catalytically Enhanced Silver-Iron (III) Oxide/Polyoxometalate/Reduced Graphene Oxide Modified Glassy Carbon Electrode

The synergism of phosphomolybdic acid hydrate (POM) decorated with silver-iron (III) oxide (Ag-Fe2O3) nanoparticles and anchored on reduced graphene oxide (RGO) have been demonstrated to be effective as a nonenzymatic H2O2 sensor platform. The assembly of the sensor components and their interactions were probed morphologically, spectroscopically and electrochemically. The Ag-Fe2O3/POM/RGO nanocomposite sensor provided an enhanced electroactive surface area, electrical conductivity and sensitivity for hydrogen peroxide compared to an unmodified glassy carbon electrode (GCE) at –0.55 V versus a saturated calomel electrode. The developed sensor amperometric response was linear across the concentration range from 0.3 mM to 3.3 mM (R2 = 0.992) with a detection limit and sensitivity of 0.2 μM and 271 μA·mM‒1·cm−2 respectively. Concomitantly, a short response time of T90 < 5 sec at a signal-to-noise ratio of 4 was achieved. The sensor was shown to determine hydrogen in the presence of interfering species, and exhibited high selectivity with relative standard deviation values less than 4.2%. The results indicate that the use of RGO to anchor and photochemically reduce POM also improved the reduction properties due to the irregular size distribution and catalytic activity of Ag-Fe2O3 stimulated by its adhesion to the distinctive POM/RGO matrix.

Electrochemical Detection of Alloxan on Reduced Graphene Oxide Modified Glassy Carbon Electrode

AbstractAlloxan is a toxic reagent that strongly induces the diabetes by destroying insulin‐producing β‐cells in the pancreas of living organisms. The reduction product of alloxan is dialuric acid, which is responsible for the intracellular generation of ROS to enhance the stress in living cells to cause kidney disease or diabetic nephropathy. Herein, we studied for the first time the electrochemical properties of alloxan on reduced graphene oxide modified glassy carbon electrode (rGO/GCE) in 0.1 M phosphate buffer solution (PBS) at pH 7. The obtained results were compared with graphene oxide modified GCE (GO/GCE) and bare GCE surfaces. The modified rGO/GCE showed well defined redox couple with 10 fold increase in both reduction as well as oxidation peak current for alloxan than that of GO/GCE and bare GCE. Differential pulse voltammetry (DPV) technique shows the linear increase in both oxidation and reduction peak current of alloxan in the range of 30 μM to 3 mM with LOD of 1.2 μM. An amperometric signal of alloxan is also increases with respect to each addition of 50 μM of alloxan on rGO/GCE at constant potential of −0.05 V. The linear range of alloxan is observed between 50 μM to 750 μM (S/N=3). This kind of rGO/GCE surface is more suitable platform or sensor matrix for estimating unknown concentration of alloxan molecule in the real biological systems.

MnO2 Nanowires-Decorated Reduced Graphene Oxide Modified Glassy Carbon Electrode for Sensitive Determination of Bisphenol A

In this paper, MnO2 nanowires-decorated reduced graphene oxide composite (MnO2 NWs-rGO) was synthesized by physical adsorption and controlled potential reduction. Means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and cyclic voltammetry (CV) were used to characterize this material. Glassy carbon electrode (GCE) modified with MnO2 NWs-rGO composite was fabricated by drop-coating method for the sensitive determination of bisphenol A (BPA). Electrochemical behaviors of BPA at the MnO2 NWs-rGO/GCE were studied using CV and chronocoulometry (CC). Experimental results found that MnO2 NWs-rGO/GCE exhibited excellent electrocatalytic activity, sensitivity, stability, and selectivity towards BPA. Under the optimized experimental conditions, quantitative analysis was carried out using the second derivative linear sweep voltammetry (SDLSV), and the MnO2 NWs-rGO/GCE revealed a good linear response to BPA concentration ranging from 0.02–20 μM and 20–100 μM, and the detection limit was 6.0 nM (S/N = 3). This new method possessed some obvious advantages, such as high determination sensitivity, simple preparation process, rapid response and low cost. The sensing performance of MnO2 NWs-rGO/GCE was demonstrated for the detection of BPA in plastic samples, and satisfactory results have been obtained. Therefore, an efficient determination method for monitoring trace levels of BPA was developed.

Novel electrochemical sensor using a dual-working electrode system for the simultaneous determination of glucose, uric acid and dopamine

Dual working electrodes were constructed for the simultaneous determination of three analytes. A graphene oxide-modified glassy carbon electrode (GO/GCE) was used for adsorptive anodic stripping voltammetry to detect uric acid and dopamine, while a chitosan/glucose oxidase/Prussian blue-graphite modified glassy carbon electrode (Chi/GOx/PB-G/GCE) was used for chronoamperometric glucose detection. The fabrication and operation conditions for both electrodes were optimized. Linearity was obtained in the ranges of 0.10–30 µM and 30–80 µM for dopamine, 0.20–10 µM and 10–30 µM for uric acid and 15–1,500 µM for glucose. The system provided detection limits (LOD = 3σ/S) of 0.080 µM, 0.11 µM, and 5.7 µM for dopamine, uric acid and glucose, respectively. This dual-working electrode system showed good reproducibility and excellent recovery for the simultaneous determination of dopamine, uric acid, and glucose. When used to analyze dopamine, uric acid, and glucose in blood plasma samples, the results agreed well with those from conventional methods (P > 0.05), indicating the potential of this system to simultaneously determine these three analytes in real samples.

Oxygen Reduction at Palladium Decorated Copper-Molybdenum Oxide Modified Glassy Carbon Electrode

In this study, metal nanoparticles decorated metal oxide electrode was fabricated via electrochemical technique. Firstly, molybdenum/copper oxide was electrochemically deposited on the bare glassy carbon electrode surface. Then palladium nanoparticles were modified on this oxide functionalized surface by consecutive potential cycles. Resulting composite electrode was characterized with scanning electron microscopy. The proposed composite electrode was employed for electrocatalytic oxygen reduction in alkaline media. As compared to bare electrode, the resulting composite surface has tremendous effect on oxygen reduction in terms of accelerated peak current values.

T-T Mismatch-Based Electrochemical Aptasensor for Ultratrace Level Detection of Hg2+ Using Electrochemically Reduced Graphene Oxide-Modified Electrode.

Ultratrace levels of mercury ions (Hg2+) were quantified utilizing differential pulse voltammetry (DPV) in aqueous solution. This method utilized a thymine (T)-rich, methylene blue-tagged DNA (MBD) and an electrochemically-reduced graphene oxide-modified glassy carbon electrode (ERGO-GCE). The ERGO-GCE was prepared by the direct reduction of graphene oxide (GO) solution on a glassy carbon electrode (GCE) using cyclic voltammetry. The MBD, as a sensing motif, was then coated on the surface of the ERGO-GCE through π-π stacking. In the presence of Hg2+, mercury-mediated coordination of the T-Hg2+-T base pairs caused folding of the MBD, leading to a hairpin structure. This resulted in subsequent unbinding of MBD from the surface of the ERGO-GCE, which produced a change in redox current of the MB tag. DPV of the modified electrode showed that the MB signal decreased linearly with increases in Hg2+ concentrations in the range between 1 fM and 100 nM with a detection limit of 0.16 fM. This sensor also exhibited excellent selectivity for Hg2+ against interfering metal ions. In addition, the sensor could be regenerated by decoupling the T-Hg2+-T in cysteine, which unfolded the MBD.

Electroanalytical Determination of Paracetamol Using Pd Nanoparticles Deposited on Carboxylated Graphene Oxide Modified Glassy Carbon Electrode

AbstractThe study presents a novel paracetamol (PA) sensor based on Pd nanoparticles (PdNPs) deposited on carboxylated graphene oxide (GO−COOH) and nafion (Nf) modified glassy carbon electrode (GCE). The morphologies of the as prepared composites were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and fourier transform infrared spectroscopy (FTIR). The experimental results demonstrated that Nf/GO−COOPd displayed excellent electrocatalytic response to the oxidation PA. The linear range was 0.04–800 μM for PA with limit of detection of 0.012 μM and excellent sensitivity of 232.89 μA mM−1 cm−2. By considering the excellent performance of Nf/GO−COOPd composite such as wider linear range, lower detection, better selectivity, repeatability, reproducibility, and storage stability, the prepared composite, especially GO−COOH support, with satisfactory electrocatalytic properties was a promising material for the modification of electrode material in electrochemical sensor and biosensor field.

Indirect Electrochemical Determination of Ribavirin Using Boronic Acid-Diol Recognition on a 3-Aminophenylboronic Acid-Electrochemically Reduced Graphene Oxide Modified Glassy Carbon Electrode (APBA/ERGO/GCE)

A novel method for the indirect electrochemical determination of ribavirin based on boronic acid-diol recognition was developed using the platform as the sensing element. The device was constructed using a 3-aminophenylboronic acid (APBA)-electrochemically reduced graphene oxide (ERGO) modified electrode. When the electrode was immersed in a solution of ribavirin, complexation of boronic acid groups of APBA with ribavirin occurred at the surface of the electrode and simultaneously caused steric hindrance, resulting in a current decrease because the ferricyanide redox probe was unable access the surface. Under the optimized conditions, a linear relationship was obtained between the relative change in current (%Δi) of [Fe(CN)6]3−/4−and the concentration of ribavirin at levels from 10.0 to 7.50 × 102 ng mL−1. The proposed electrochemical sensor performed with acceptable sensitivity and reproducibility and was successfully used to determine the content of ribavirin in an injection with satisfactory results.

Electrochemical Determination of Paracetamol at Poly(3-Methylthiophene)/Reduced Graphene Oxide Modified Glassy Carbon Electrode

Poly(3-methylthiophene)/reduced graphene oxide (P3MT/RGO) modified glassy carbon electrode (GCE) was fabricated via a facile procedure. P3MT was directly electrodeposited on the RGO coated electrode and employed for the electrochemical detection of paracetamol (PCT). The morphology of composite was characterized by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrochemical behaviors of PCT on P3MT/RGO/GCE. Experimental parameters, such as the scan rates, polymerization laps and the pH of buffer solution were optimized. Under the optimal conditions, the anodic peak current in DPVs varies linearly with the concentration of PCT, and the limit of detection was 0.025[Formula: see text][Formula: see text]M. Moreover, the proposed P3MT/RGO/GCE also exhibited superior stability and reproducibility.