Modified Glassy Carbon Electrode Research Articles

Co-operation of electrochemistry and chemometrics to develop a novel electrochemical aptasensor based on generation of first- and second-order data for selective and sensitive determination of the prostate specific antigen biomarker

In this work, a novel electrochemical aptasensor was fabricated based on modification of glassy carbon electrode with prostate specific antigen (PSA) binding DNA aptamer (5′-HS-(CH2)6-TTTTTA ATT AAA GCT CGC CAT CAA ATA GCTTT-3′)/gold nanoparticles/electrochemically reduced fullerene-C60/multi-walled carbon nanotubes- ionic liquid-graphene (APT/Au NPs/C60/MWCNTs-IL-Gr/GCE). By incubation of the aptasensor with the PSA and binding of the PSAs with the APTs, steric hindrance at the aptasensor was increased therefore, the voltammetric response of the aptasensor immersed in the electrochemical probe solution was decreased. Three electrochemical methods including differential pulse voltammetry (DPV), square wave voltammetry (SWV) and amperometry were used to assist the aptasensor for determination of the PSA, and the best one was chosen for the analysis of real matrices. Second-order DPV data, first-order SWV and amperometric data were generated and used to assist the aptasensor. Second-order DPV data were modeled by PARAFAC2 and MCR-ALS while SWV and amperometric data were modeled based on classical univariate calibration methods to build the calibration models. After evaluation of the performances of different calibration models in the analysis of synthetic samples, the second-order calibration based on DPV data modeled by MCR-ALS was chosen as the best calibration model to assist the aptasensor for the analysis of serum samples as real matrices. Fortunately, the aptasensor assisted by MCR-ALS had a very good performance for the determination of the PSA in serum samples which was comparable with a reference method.

Electroanalytical Determination of Ziram by Differential Pulse Voltammetry with Reduced Graphene Oxide/Gold Nanoparticles Modified Glassy Carbon Electrode

The preparation of gold nanoparticles-reduced graphene oxide-based sensor materials for the determination of zinc(II)dimethyldithiocarbamate (ziram) is described in this paper. The graphene oxide (GO) was synthesized using a modified Hummer's method. A composite sensor consisting of gold nanoparticles (AuNPs) and reduced graphene oxide (RGO) was electrochemically fabricated on a glassy carbon electrode. The nanocomposite was evaluated utilizing scanning electron microscopy (SEM). Cyclic voltammetry was used to illuminate the modified sensor's electrochemical properties at each stage of the modification. The suggested sensor was demonstrated good analytical performance to determine ziram pesticide in water and peach juice, including a very low detection limit, a large linear range, and a low RSD.

Electrochemical Behavior and Ultrasensitive, Simple and Effective Voltammetric Determination of Acetaminophen Using Modified Glassy Carbon Electrode Based on 4‐Hydroxyquinoline‐3‐carboxylic Acid

AbstractAn electrochemical oxidation of acetaminophen (ACOP) has been successfully performed by using glassy carbon electrode covered with 4‐hydroxyquinoline‐3‐carboxylic acid (4HQ3CA) to reinforce electrode's feature. To characterize the modified electrode (4HQ3CA/GC), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Fourier transform infrared spectroscopy (FT‐IR) techniques were used. The finding optimum conditions (supporting electrolyte, pH) and the electrochemical determination studies were performed with differential pulse voltammetry (DPV). It was decided that the supporting electrolyte medium suitable for ACOP determination was Britton‐Robinson (BR) buffer and the effect of pH change on the oxidation peak of ACOP in this media was investigated. The effect of changing scan rate on the oxidation peak of ACOP was examined and this study showed that the oxidation process of ACOP on the 4HQ3CA/GC modified electrode surface was diffusion and adsorption controlled process. A wide concentration range from 0.0025 μM to 141 μM with a limit of detection (LOD) of 5.98×10−10 M (3 s/m) was obtained. This prepared sensor was carried out for the determination of ACOP in pharmaceutical sample.

Potentiodynamic Poly(resorcinol)-Modified Glassy Carbon Electrode as a Voltammetric Sensor for Determining Cephalexin and Cefadroxil Simultaneously in Pharmaceutical Formulation and Biological Fluid Samples.

This study covers the development of a fast, selective, sensitive, and stable method for the simultaneous determination of cephalosporins (cephalexin (CLN) and cefadroxil (CFL)) in biological fluids and tablet samples using potentiodynamic fabrication of a poly(resorcinol)-modified glassy carbon electrode (poly(reso)/GCE). The results of cyclic voltammetry and electrochemical impedance spectroscopy supported the modification of the GCE by a polymer layer that raised the electrode surface area and conductivity. At the poly(reso)/GCE, an irreversible oxidative peak with four- and fivefold current enhancement for CLN and CFL, respectively, at a substantially lower potential demonstrated the catalytic action of the modifier. Under optimized solution and parameters, the peak current response at the poly(reso)/GCE revealed a linear dependence on the concentration of CLN and CFL within the range 0.1–300 and 0.5–300 μM, respectively, with a limit of detection (LoD) of 3.12 and 8.7 nM, respectively. The levels of CLN in four selected tablet brands and CFL in two tablet brands were in the vicinity of 91.00–103.65% and 97.7–98.83%, respectively, of their nominal values. The recovery results for CLN in pharmaceutical samples were in the range of 99.00–100.67% and for CFL 97.9–99.75% and for blood serum and urine samples 99.55–100.55% and 99.33–100.34% for CLN and 97.13–100.60% and 96.73–102.50% for CFL, respectively. Interference recovery results with errors less than 4.81%, lower LoD, wider dynamic range, excellent recovery results, and good stability of the modifier compared to those for the previously reported methods validated the use of the poly(reso)/GCE for determining CLN and CFL simultaneously in various real samples.

Spontaneous Decarboxylation of Ferrocenecarboxylate using 1,4‐Benzoquinone as Oxidant: Application to the Chemical Grafting of Glassy Carbon Surfaces

AbstractThe covalent modification of glassy carbon electrode with ferrocenyl moieties was performed in acetonitrile using a mixture of ferrocenecarboxylate (FcCOO−) and ferrocenecarboxylic acid (FcCOOH). This process is activated by 1,4‐benzoquinone (Q), which plays the role of oxidant. The carboxylate induces the redox reduction of the quinone whereas an excess of the carboxylic acid drives the protonation of the reduced quinone to yield hydroquinone (QH2) as a reaction product. Due to the homogeneous oxidation of the carboxylate derivative, carbon dioxide and ferrocenyl radicals (Fc⋅) are released, such as occurs in the classical Kolbe reaction. The generation of ferrocenyl radicals allows the chemical derivatization of non‐connected glassy carbon surfaces. The homogeneous redox reaction between the 1,4‐benzoquinone and ferrocenecarboxylate proceeded slowly and permitted the covalent attachment of a thin film with ferrocenyl moieties, whose presence on the carbon surface was evidenced from cyclic voltammetry and atomic force microscopy (AFM) measurements.

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

Synthesized Cobalt Tetroxide-Graphene Composite Film by Electrospinning and Modified Glassy Carbon Electrode for Ofloxacin Determination

The purpose of this study was to determinate ofloxacin, the approach of electrospinning and electrochemical was adopted, metal oxide cobalt tetroxide (Co3O4)/graphene (GR) nanomaterials were electrodeposited on the surface of glassy carbon electrode, then prepared a new type of nanocomposite electrode (Co3O4/GR/GCE), it was successfully used to measure ofloxacin. The experiments show that the surface morphology of the modified electrode was characterized by scanning electron microscopy, and the Co3O4 nanoparticles and GR could be well modified on the surface of the glassy carbon electrode. The determination conditions of ofloxacin were optimized by the differential pulse voltametry (DPV). Under the optimal conditions, the linear relationship ranged from 0.45 to 170 μM, and the minimum detection limit was 0.16 μM (S/N = 3). Moreover, the recovery rate in the actual drug was good, and the relative standard deviations were all less than 5%. The impacts of the obtained results indicate that the modified electrode has good electrocatalytic performance for ofloxacin, and has good repeatability and practicability, and can significantly improve the detection sensitivity.

Highly Sensitive and Selective Electrochemical Determination of Uric Acid in the Presence of Ascorbic Acid and Dopamine Using a Copper Nanoparticle-Tartrazine Nanocomposite Modified Glassy Carbon Electrode by Differential Pulse Voltammetry

A new electrochemical biosensor was designed for the determination of uric acid by modifying the surface of the glassy carbon electrode with electrodeposited tartrazine and copper nanoparticles (Cu NPs/TAT) nanocomposite. Electrochemical investigations were administered using cyclic voltammetry and differential pulse voltammetry. The modified Cu NPs/TAT nanocomposite electrode was characterized by field emission scanning electron microscopy, mapping, X-ray diffraction, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy, and electrochemical impedance spectroscopy. The results showed an increase in surface conductivity. The modified electrode had linear ranges from 0.03 to 97 µM with a sensitivity of 0.258 µA µM−1 and from 115 to 1100 µM with a sensitivity of 0.0368 µA µM−1. The modified electrode showed a detection limit as low as 2.9 nM at a signal-to-noise ratio of three. In the interference study, this modified electrode had the ability to separate dopamine, uric acid, and ascorbic acid peaks. In addition, the sensor displayed high selectivity and sensitivity, good repeatability, and good stability, and was employed for uric acid determination in human serum samples with satisfactory results.

Design of an Electrochemical Sensor for the Determination of Riboflavin using Cobalt Doped Dysprosium Oxide Nanocubes Modified Glassy Carbon Electrode

AbstractThis study explains the synthesis of cobalt‐doped dysprosium oxide nanocubes (Co‐Dy2O3 NCs) and the modification of GCE (glassy carbon electrode), for the selective and sensitive detection of riboflavin (RF). The Co‐Dy2O3 NCs were synthesized by co‐precipitation method and characterized using spectroscopic and microscopic techniques like micro‐Raman Spectroscopy, X‐ray diffraction (XRD), X‐ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FT‐IR), High‐Resolution Transmission Electron Microscopy (HRTEM), Energy‐Dispersive X‐ray Spectroscopy (EDX), and High Resolution Scanning Electron Microscopy (HRSEM). The synthesized Co‐Dy2O3 NCs were coated on the glassy carbon electrode to detect and quantify the concentration of riboflavin in aqueous and real samples. The samples were analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques with three‐electrode system. The modified electrode displays two linear concentration ranges (0.5–50, 50–300 μM) with a low detection limit (LOD) of 0.094 μM and high sensitivity of 3.67 μA μM−1 cm−2. Besides, the fabricated sensor has more selectivity, great reproducibility, repeatability and good stability. Finally, the Co‐Dy2O3 NCs modified GCE based sensor was effectively applied in real sample analysis using milk and egg yolk with good recovery.

Electrosynthesis of ternary nonprecious Ni, Cu, Fe oxide nanostructure as efficient electrocatalyst for ethanol electro-oxidation: Design strategy and electrochemical performance

Materials composed of various constituents with distinct physical or chemical features are named composites. Merging components in the composite structure leads to new properties creation or the intrinsic properties magnification of the components, or synergetic effects. Here, the ternary nanocomposite of copper, nickel, and iron oxides was electrodeposited on the glassy carbon electrode (GCE) surface to facilitate the ethanol electro-oxidation reaction (EOR) and overcome the electrode fouling problem while prolonging its efficiency. The GCEs were modified by three different procedures and activated by CV cycling in an alkaline solution, and their electro-catalytic activity was tested toward EOR. The ternary electrocatalysts prepared by two-steps electrodeposition of their components (Ni,Fe2O3/Cu and Cu/Ni,Fe2O3) demonstrated higher peak current and more negative peak potential (Epa = 476 mV, Ipa = 492 μA, and Epa = 510 mV, Ipa = 644 μA, respectively) than the binary electrocatalyst of Ni,Fe2O3 toward EOR. The best electro-catalytic efficiency was acquired for the simultaneous electrodeposition of nano Cu, Ni, and Fe2O3 on the GCE surface (Cu,Ni,Fe2O3, Epa = 530 mV, Ipa = 3179 μA). The physicochemical and electro-catalytic characterizations of the fabricated electrocatalysts were evaluated by various techniques. The fast and facile engineered design of the GCE modification with the ternary Cu,Ni,Fe2O3 components led to a high current density of about 101 mA/cm2 with increased tolerance against poisoning intermediates resulting in longtime stability for EOR in alkaline media. The synergistic effect between nano Ni, Cu, and Fe oxides provided promising properties for the EOR pursuing the construction of a powerful device with commercialization potential.

Poly L- methionine/Electrochemically Reduced Graphene Oxide Composite Film Modified Glassy Carbon Electrode for the Simultaneous Determination of 5-hydroxyindole Acetic Acid and Tyrosine

An effective electrochemical sensor based on “poly L- methionine/Electrochemically Reduced Graphene Oxide Composite Film Modified Glassy Carbon Electrode (poly(L-Met)/ERGO/GCE))” has been developed for the individual and simultaneous determination of 5-hydroxyindole acetic acid (5-HIAA) and tyrosine (Tyr). In clinical point of view, simultaneous determination of these analytes is very important and a sensor for the same is not reported yet. This sensor offers sensitive, reproducible and selective determination of 5-HIAA and Tyr. Experimental parameters for the effective determination of the analytes were optimized. Under optimized conditions, quantification of 5-HIAA is possible within the range 1.0 × 10−5 M to 8.0 × 10−7 M and for Tyr in two ranges, 1.0 × 10−5 M to 5.0 × 10−6 M and 7.0 × 10−5 M to 2.0 × 10−5 M. The limit of detection and limit of quantification obtained for 5-HIAA using poly(L-Met)/ERGO/GCE are 5.0 × 10−7 M and 8.0 × 10−7 M respectively, and for Tyr, 1.0 × 10−6 M and 5.0 × 10−6 M respectively. The sensor was successfully applied for the determination of both 5-HIAA and Tyr in artificial urine and blood serum samples.

A Novel Electrochemical Sensor for Detection of Nicotine in Tobacco Products Based on Graphene Oxide Nanosheets Conjugated with (1,2-Naphthoquinone-4-Sulphonic Acid) Modified Glassy Carbon Electrode.

A simple electrochemical sensor for nicotine (NIC) detection was performed. The sensor based on a glassy carbon electrode (GCE) was modified by (1,2-naphthoquinone-4-sulphonic acid)(Nq) decorated by graphene oxide (GO) nanocomposite. The synthesized (GO) nanosheets were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR, and UV-Visible Spectroscopy. The insertion of Nq with GO nanosheets on the surface of GCE displayed high electrocatalytic activity towards NIC compared to the bare GCE. NIC determination was performed under the optimum conditions using 0.10 M of Na2SO4 as a supporting electrolyte with pH 8.0 at a scan rate of 100 mV/s using both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This electrochemical sensor showed an excellent result for NIC detection. The oxidation peak current increased linearly with a 6.5–245 µM of NIC with R2 = 0.9999. The limit of detection was 12.7 nM. The fabricated electrode provided satisfactory stability, reproducibility, and selectivity for NIC oxidation. The reliable GO/Nq/GCE sensor was successfully applied for detecting NIC in the tobacco product and a urine sample.

Highly Sensitive Determination of Niclosamide Based on The Graphitized and Carboxylated Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

Highly Sensitive Determination of Niclosamide Based on The Graphitized and Carboxylated Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

Voltammetric Assessment of 8-Oxoguanine at a Nano-Structured Carbon Materials Based Modified Glassy Carbon Electrode

In this study, we have investigated the voltammetric behavior of 8-Oxoguaine on a Multi walled carbon nanotubes / Carbon black modified glassy carbon electrode. The voltammetric oxidation of 8-Oxoguaine on modified electrode was electro-catalytic in nature. The voltammetric oxidation of the substrate was a pH dependent reversible process. Using cyclic voltammetry, a method for the determination of 8-Oxoguaine was developed. At a pH of 7.4 in phosphate buffer solution, the concentration of 8-Oxoguanine was linear from 30 to 100 μM. The detection limit and quantification limit of 8.38 μM and 27.95 μM were obtained from calibration graph, respectively. The modified electrode shows good recovery and reproducibility with relative standard deviation of 2.12%. The inter-day and intra-day assays were also studied.

Hydroxyapatite/L-Lysine Composite Coating as Glassy Carbon Electrode Modifier for the Analysis and Detection of Nile Blue A.

An amperometric sensor was developed by depositing a film coating of hydroxyapatite (HA)/L-lysine (Lys) composite material on a glassy carbon electrode (GCE). It was applied for the detection of Nile blue A (NBA). Hydroxyapatite was obtained from snail shells and its structural properties before and after its combination with Lys were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analyses. The coupling of Lys to HA was attributed to favorable interaction between negatively charged -COO− groups of Lys and divalent ions Ca2+ of HA. Electrochemical investigations pointed out the improvement in sensitivity of the GCE/Lys/HA sensor towards the detection of NBA in solution. The dependence of the peak current and potential on the pH, scan rate, and NBA concentration was also investigated. Under optimal conditions, the GCE/Lys/HA sensor showed a good reproducibility, selectivity, and a NBA low detection limit of 5.07 × 10−8 mol L−1. The developed HA/Lys-modified electrode was successfully applied for the detection of NBA in various water samples.

A new molecularly imprinted polymer electrochemical sensor based on CuCo2 O4 /N-doped CNTs/P-doped GO nanocomposite for detection of 25-hydroxyvitamin D3 in serum samples.

25-Hydroxyvitamin D3 as a main circulating metabolite of vitamin D is usually measured in serum to evaluate the vitamin D status of humans. So, developing an accessible, fast response, sensitive, and selective detection method for 25-hydroxyvitamin D3 is highly important. In this study, we designed a sensitive and selective electrochemical sensor based on the modification of glassy carbon electrode by nanocomposite of CuCo2 O4 /nitrogen-doped carbon nanotubes and phosphorus-doped graphene oxide. Then 25-hydroxyvitamin D3 -imprinted polypyrrole was coated on the electrode surface through electropolymerization. Moreover, ferricyanide was used as a mediator for the creation of a readable signal, which was considerably decreased after rebinding of 25-hydroxyvitamin D3 on the electrode. The proposed sensor successfully detected 25-hydroxyvitamin D3 in the range of 0.002-10μM, with a detection limit of 0.38nM, which was highly lower than deficiency concentration (20ng/ml; 49.92nM). Finally, the proposed sensor was checked for detection of 25-hydroxyvitamin D3 in serum samples with recovery in the range of 80%-106.42%. The results demonstrated the applicability of the designed sensor for the detection of 25-hydroxyvitamin D3 in biological samples.

Surface Modification of Glassy Carbon Electrode Using Hematoxylin and MWCNTs/Fe3O4/TiO2 Nanocomposite; a Sensitive Electrochemical Technique for Detection of Methyldopa in the Presence of Folic Acid

Surface Modification of Glassy Carbon Electrode Using Hematoxylin and MWCNTs/Fe3O4/TiO2 Nanocomposite; a Sensitive Electrochemical Technique for Detection of Methyldopa in the Presence of Folic Acid

Fabrication of Methyl Parathion Electrochemical Sensor Based on Modified Glassy Carbon Electrode with Graphitized and Carboxylated Multi-Walled Carbon Nanotubes Decorated with Zirconia Nanoparticles

Fabrication of Methyl Parathion Electrochemical Sensor Based on Modified Glassy Carbon Electrode with Graphitized and Carboxylated Multi-Walled Carbon Nanotubes Decorated with Zirconia Nanoparticles

Coral reef-like zinc niobate nanostructures decorated functionalized carbon nanofiber as electrode modifier for detection of oxidative stress biomarker: 3-nitro-L-tyrosine

Oxidative stress can transform immunologic disorders to malignancy by enhancing the effect of pathogenic factors associated with adverse health problems. Biomarkers generated during oxidative stress are essential in assessing the in vivo condition of the cell for evaluating health and diagnosing the disease at an early stage, prognosis, benign and effectual drug development, and testing the drug efficacy. 3-Nitro-L-tyrosine is an oxidative stress biomarker produced from L-tyrosine through nitration mediated by active metabolites. Thus, precise detection of 3-NO2-Tyr in the biological medium is significantly important to monitor the cell environment. Consequently, a novel electrochemical sensing platform had been designed using ZnNb2O6 nanostructures anchored f-CNF as a glassy carbon electrode modifier. The crystalline and structural features, morphology, and elemental composition of ZnNb2O6/f-CNF nanocomposite were keenly verified. The synchronic activation of ZnNb2O6/f-CNF nanocomposite for effective detection of 3-NO2-Tyr is mainly due to the synergic effect between its counterparts. Accordingly, the fabricated sensor possesses a remarkably low limit of detection (0.021 μM) with a good linear range, and sensitivity is noted to be 7.745 μA/μM⋅cm⁻2. The consistency of this sensor was evinced through real-time monitoring of 3-NO2-Tyr in urine and saliva samples which is beneficial in monitoring the pathological situation.

The Modified Glassy Carbon Electrode by MWCNTs-PLL to Detect Both Paracetamol and Ibuprofen in Human Biological Fluid

The MWCNTs-PLL material was effectively synthesized in this study. The UV–vis spectrum and FT-IR spectroscopy are used to determine the structure of nanoparticles. The electrochemical characteristics of glassy carbon electrodes (GCE) were examined after the MWCNTs-PLL material with nanosized particles was dropped onto its surface to create MWCNTs-PLL/GCE. Furthermore, employing electrodes, PAR and IBU were examined via applying CV and DP-ASV techniques. In comparison to employing the bare GCE, the modified MWCNTs-PLL/GCE electrode showed good responsiveness toward PAR and IBU applying the DP-ASV technique, with LODs were 0.40 for PAR, 0.34 μM for IBU. The linear concentrations ranged from 1.0 to 210 μM. These factors like Na+, SO4 2−, CO3 2−, K+, Ca2+, Cl−, Mg2+, NH4 +, NO3 − ions, uric acid, oxalate and AA, did not interfere during the modified electrode’s operation. Within this paper, it is worth emphasizing that these analytical processes for the PAR and IBU in practical sample solutions are more dependable than the HPLC tool. Additionally, this work would be considered the state-of-the-art study for both using MWCNTs-PLL to simultaneously determine PAR and IBU, and employing successfully the cheap, fast, reliable method.