Activated Glassy Carbon Electrode Research Articles

Electrochemical Characterization and Detection of Ascorbic Acid in Garlic Using Activated Glassy Carbon Electrode: a Comprehensive Study

Electrochemical Characterization and Detection of Ascorbic Acid in Garlic Using Activated Glassy Carbon Electrode: a Comprehensive Study

Kinetics of Electrocatalytic Oxygen Reduction Reaction over an Activated Glassy Carbon Electrode in an Alkaline Medium

Hydrogen peroxide is a promising substitute for fossil fuels because it produces non-hazardous by-products. In this work, a glassy carbon GC was anodized in sulphuric acid at +1.8 V to prepare the working electrode. It was utilized to investigate the oxygen reduction reaction (ORR) in a basic medium containing 0.1 M NaOH as a supporting electrolyte. The objective of this investigation was to synthesize hydrogen peroxide. X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), linear polarization, cyclic voltammetry (CV), and rotating disk electrode voltammetry (RDE) were performed for characterization and investigation of the catalytic properties. The RDE analysis confirmed that oxygen reduction reactions followed two electrons’ process at an activated GC electrode. Hence, the prepared electrode generated hydrogen peroxide from molecular oxygen at a potential of around −0.35 V vs. Ag/AgCl (sat. KCl), significantly lower than the pristine GC surface. The transfer coefficient, standard reduction potential, and standard rate constant were estimated to be 0.75, −0.27 V, and 9.5 × 10−3 cm s−1, respectively.

Simultaneous Determination of Ranitidine and Metronidazole at Low Potential Using an Acid‐Activated Glassy Carbon Electrode

AbstractA simple, highly sensitive and inexpensive electrochemical method was established using an activated glassy carbon electrode (AGCE) in an acidic condition for the determination of ranitidine (RT) and metronidazole (MT) simultaneously at a low potential range. The AGCE was characterized using various techniques such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and morphology was studied through field‐emission scanning electron microscope (FE‐SEM). The AGCE exhibited an electrocatalytic behavior towards the reduction of RT and MT in 0.5 M acidic solution. Both CV and DPV responses for the mixture of RT and MT gave well‐resolved peaks at low potential. Analysis of these experiments helps us to predict interactions that took place on the surface of AGCE and RT and MT with each other for having different types of functional groups. Furthermore, AGCE also promoted the electron transfer process. The linear dynamic range of MT and RT was 0.5–580 μM and 0.5–500 μM, respectively with the regression coefficient 0.99. The detection limit (S/N=3) calculated for MT and RT was 0.062 μM and 0.13 μM, respectively. Decent results were obtained from the reproducibility and stability test. The performance of the sensor was evaluated for the possible interferences which show high selectivity. Additionally, the real sample analysis was carried out to understand our sensor‘s applicability in real life.

Electroanalysis of Flutamide as an Anticancer Drug at Electrochemically Activated Glassy Carbon Electrode

Electroanalysis of Flutamide as an Anticancer Drug at Electrochemically Activated Glassy Carbon Electrode

Activated Glassy Carbon Electrode as an Electrochemical Sensing Platform for the Determination of 4-Nitrophenol and Dopamine in Real Samples.

Glassy carbon electrode (GCE) was electrochemically activated using a repetitive cyclic voltammetric technique to develop an activated glassy carbon electrode (AGCE). The developed AGCE was optimized and utilized for the electrochemical assay of 4-nitrophenol (4-NP) and dopamine (DA). Cyclic voltammetry (CV) was employed to investigate the electrochemical behavior of the AGCE. Compared to the bare GCE, the developed AGCE exhibits a significant increase in redox peak currents of 4-NP and DA, which indicates that the AGCE significantly improves the electrocatalytic reduction of 4-NP and oxidation of DA. The electrochemical signature of the activation process could be directly associated with the formation of oxygen-containing surface functional groups (OxSFGs), which are the main reason for the improved electron transfer ability and the enhancement of the electrocatalytic activity of the AGCE. The effects of various parameters on the voltammetric responses of the AGCE toward 4-NP and DA were studied and optimized, including the pH, scan rate, and accumulation time. Differential pulse voltammetry (DPV) was also utilized to investigate the analytical performance of the AGCE sensing platform. The optimized AGCE exhibited linear responses over the concentration ranges of 0.04–65 μM and 65–370 μM toward 4-NP with a lower limit of detection (LOD) of 0.02 μM (S/N = 3). Additionally, the AGCE exhibited a linear responses over the concentration ranges of 0.02–1.0 and 1.0–100 μM toward DA with a lower limit of detection (LOD) of 0.01 μM (S/N = 3). Moreover, the developed AGCE-based 4-NP and DA sensors are distinguished by their high sensitivity, excellent selectivity, and repeatability. The developed sensors were successfully applied for the determination of 4-NP and DA in real samples with satisfactory recovery results.

Highly Sensitive Electrochemical Sensor for Sunset Yellow Based on Electrochemically Activated Glassy Carbon Electrode.

Electrochemically activated glassy carbon electrode (AGCE) was fabricated and applied for sensitive and selective detection of sunset yellow (SY). The electroanalysis of SY was investigated by square wave voltammetry (SWV). Owed to the specific oxygen-contained functional groups and the outstanding conductivity of AGCE, the proposed sensor exhibits an enhanced oxidation peak current of SY when compared with non-activated glass carbon electrode (GCE). Under the optimal analytical conditions, the oxidation peak current is linear with SY concentration in the range of 0.005–1.0 μM. The low limit of detection is 0.00167 μM (S/N = 3). This method is applied for the detection of SY in the actual samples. The recovery is between 96.19 and 103.47%, indicating that AGCE is suitable for the determination of SY in beverage sample.

Electrochemical Detection of H2O2 Using an Activated Glassy Carbon Electrode

Hydrogen peroxide (H2O2) is extensively used for sterilization purposes in the food industries and pharmaceuticals as an antimicrobial agent. According to the Food and Agriculture Organization (FAO), the permissible level of H2O2 in milk is in the range of 0.04 to 0.05% w/v, so it has been prohibited to use as a preservative agent. Herein, we reported the electrochemical sensing of H2O2 in milk samples using an activated glassy carbon electrode (AGCE). For this purpose, activation of GCE was carried out in 0.1 M H2SO4 by continuous potential sweeping between −0.7 to 1.8 V for 25 cycles. The AGCE showed a redox peak at -0.18 V in the neutral medium corresponding to the quinone functional groups present on the electrode surface. AGCE was studied in (pH 7.4) 0.1 M PBS for the electro-catalysis of H2O2. The surface of the activated electrode was analysed by Raman spectroscopy and contact angle measurements. In addition, for the activated surface, the contact angle was found to be 85° which indicated the hydrophilic nature of the surface. The different optimization parameters such as (1) effect of electrolyte ions, (2) electrooxidation cycles, and (3) oxidation potential windows were studied to improve the activation process. Finally, AGCE was used to detect H2O2 from 0.1 to 10 mM and the limit of detection (LOD) was found to be 0.053 mM with a linear correlation coefficient (R2) of 0.9633. The selectivity of the sensor towards H2O2 was carried out in the presence of other interferents. The sensitivity of the AGCE sensor was calculated as 17.16 μA mol cm−2. Finally, the commercial application of the sensor was verified by testing it in milk samples with H2O2 in the recovery range of 95%–98%.

Sensor based on Copper Nanoparticles Modified Electrochemically Activated Glassy Carbon Electrode for Paracetamol Determination

Sensor based on Copper Nanoparticles Modified Electrochemically Activated Glassy Carbon Electrode for Paracetamol Determination

Sensitivity Control of Hydroquinone and Catechol at Poly(Brilliant Cresyl Blue)-Modified GCE by Varying Activation Conditions of the GCE: An Experimental and Computational Study

The poly(brilliant cresyl blue) (PBCB)-modified activated glassy carbon electrode (AGCE) shows the catalytic activity toward the oxidation of hydroquinone (HQ) and catechol (CT). The modified electrode can also separate the oxidation peaks of HQ and CT in their mixture, which is not possible with bare GCE. These properties of the modified electrode can be utilized to fabricate an electrochemical sensor for sensitive and simultaneous detection of HQ and CT. In this study, an attempt is made to control the sensitivity of the modified electrodes. This can be accomplished by simply changing the activation condition of the GCE during electropolymerization. GCE can be activated via one-step (applying only oxidation potential) and two-step (applying both oxidation and reduction potential) processes. When we change the activation condition from onestep to twosteps, a clear enhancement inpeak currents of HQ and CT is observed. This helps us to fabricate a highly sensitive electrochemical sensor for the simultaneous detection of HQ and CT. The molecular dynamics (MD) simulation is carried out to explain the experimental data. The MD simulations provide the insight adsorption phenomena to clarify the reasons for higher signals of CT over HQ due to having meta-position –OH group in its structure.

Determination of Chloramphenicol by a New Electrochemically Activated Glassy Carbon Electrode in Sodium Sulfate Medium

In this paper, a two-step method combining potentiometry and cyclic voltammetry (CV) was used to prepare the activated glassy carbon electrode (GCE), and a new and simple analytical method for the determination of chloramphenicol (CAP) by using the activated GCE in the new activation medium of 0.1 mol l−1 Na2SO4 was established. The optimum activation conditions were as follows: polarized at 1.75 V (vs SCE) for 320 s and scanned for 10 cycles in the potential ranging from −1.2 V to 1.0 V with CV at 150 mV s−1. Afterward, the electrochemically Na2SO4 medium activated GCE (SSA-GCE) was prepared. The reduction peak current of CAP at −0.64 V (vs SCE) was 13.11 times higher than that of bare GCE under the optimal analytical conditions. The prepared SSA-GCE showed fast surface electron transfer rate, high repeatability, good stability with linear ranges of 0.2 to 2 μmol l−1 and 2 to 50 μmol l−1, and detection limit (S/N = 3) of 0.017 μmol l−1. The SSA-GCE was applied in the detection of CAP in aquaculture water. The recovery was between 95.0% and 103.6%, indicating that SSA-GCE was suitable for the determination of CAP in aquaculture water, and the mechanism of electrode reaction was discussed.

Glassy Carbon Electrode Electromodification in the Presence of Organic Monomers: Electropolymerization versus Activation.

Several reports in the literature deal with the modification of glassy carbon electrode (GCE) surface via electropolymerization of some organic monomers, particularly p-aminobenzenesulfonic acid (p-ABSA) and l-cysteine using intensive oxidative conditions, and attributed the improved electrocatalytic activities toward various analytes to the formation of the electropolymerized layer. What is the real cause for this improvement in electrocatalytic activity? Is it because of the electrochemical activation process of GCE or electropolymerization? Combining a set of surface and electrochemical characterization techniques, we first showed that the electrochemical peaks previously assigned in many reports to electropolymerization processes at the surface of GCE correspond to electrochemical activation of the GCE surface. We further demonstrated that the anodization of GCE at high voltage causes activation of its surface and the formation of surface functional groups (SFGs). In fact, those SFGs are found to be the main reason for the enhancement in electrocatalytic activity of the activated GCE (AGCE). The surface features of the modified electrodes were characterized by Raman spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The electrochemical behavior was investigated using cyclic voltammetry (CV). The analytical performance of AGCE toward dopamine (DA) was assessed using differential pulse voltammetry (DPV). As compared to the previously reported dopamine electrochemical sensors assuming such electropolymerization processes, the AGCE showed analytical performance practically similar to that of these sensors. This further confirms that the enhancement in electrocatalytic activity is due to the electrochemical activation of the GCE surface.

Poly (brilliant cresyl blue)-reduced graphene oxide modified activated GCE for nitrite detection: Analyzing the synergistic interactions through experimental and computational study

In this article, theoretical and computational (CP) analysis were carried out on the experimental data for the nonenzymatic oxidation of nitrite at the modified electrode to better understand the underlying chemistry. We studied the kinetics of the electron transfer process through various electroanalytical techniques and simulated the cyclic voltammetry (CV) data using Butler-Volmer equation. The CP methods were used for understanding the molecular interaction processes at the electrode-electrolyte interface. The modified electrodes were developed by the electrodeposition of poly (brilliant cresyl blue) (PBCP) on an electrochemically reduced graphene oxide (ERGO) at the activated glassy carbon electrode (AGCE) (AGCE/ERGO/PBCB). The AGCE/ERGO/PBCB sensor was characterized through electrochemical and electron microscopy methods. Analysis of the characterization data supported our assumption, that AGCE is the better platform for the optimal electrochemical reduction of GO compared to the GCE for the purpose of the electropolymerization process. Simulated CV showed that the oxidation process followed a 2e− transfer pathway, but the electron transfer took place in a step wise manner. While, CP data revealed that the AGCE, ERGO, and PBCB interacted with each other through the parallel-displaced and sandwich types π – π stacking, and electrostatic interactions. H⋯O–H, and H⋯N–H hydrogen bonds between the functional groups of AGCE, and ERGO also promoted the electron transfer process. The AGCE/ERGO/PBCB was then used for the nonenzymatic detection of the nitrite species in the acidic medium using amperometric and CV techniques. The sensor was also tested for real sample analysis.

Simultaneous Detection of Hydroquinone, Catechol and Resorcinol by an Electrochemical Sensor Based on Ammoniated-Phosphate Buffer Solution Activated Glassy Carbon Electrode

Abstract An electrochemical sensor was successfully fabricated by coupled ammoniated modification with PBS activation on glassy carbon electrodes (CA-GCE) and characterized by electrochemical impedance spectra. The CA-GCE showed outstanding electrochemical performance, and was applied to simultaneous detection of resorcinol (RC), catechol (CC) and hydroquinone (HQ), which could be ascribed to new active sites by the introduction of amino and oxygen-containing groups and H-bonds formed between hydroxyl groups of RC, CC, and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. The reaction kinetics of RC, CC, and HQ and their reaction on CA-GCE were studied. Experimental results showed that the electrochemical reaction was adsorption controlled. Under the optimal conditions, the linear detection ranges for RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, respectively, with their detection limits of 0.47, 0.23 and 0.46 μM, respectively. Interference and repeatability was further investigated. This strategy opened a new horizon for qualitative and quantitative detection of dihydroxy benzene.

Adsorptive square wave voltammetric determination of amitraz in Argentine honeys with a microwave-assisted sample treatment

The main goal of this work is the development of an electroanalytical method for the amitraz determination in honey samples by quantification its final metabolite, 2,4 dimethylaniline. An electrochemically activated glassy carbon electrode (AGCE) as working electrode and adsorptive square wave voltammetry (ASWV) technique were used. A simple and fast microwave-assisted pretreatment of the samples was presented to accelerate the amitraz hydrolysis to 75 s. The ASWV parameters were optimized based on a “Box-Benkhen” design. The ASWV response was linear in the hydrolyzed amitraz concentration range from 0.25 to 2.50 μM with a limit of detection (LOD) of 0.19 μM. The proposed method is a simple and low-cost alternative for the determination of amitraz residues in Argentine honeys samples. Recovery experiments were performed using spiked honey samples with recoveries from 91.41 to 108.6%.

Simple and sensitive determination of hydroxyl radical in atmosphere based on an electrochemically activated glassy carbon electrode

ABSTRACTThe hydroxyl radical (•OH) plays important roles in environment and health problems. However, the short life time and low concentrations of •OH limited its detection. In this work, a simple method has been successfully performed for the sensitive detection of hydroxyl radical based on an activated glassy carbon electrode (AGCE).4-hydroxybenzoic acid (4-HBA) was used as a trapping agent for •OH radicals, leading to the production of electroactive 3,4-dihydroxybenzoic acid (3,4-DHBA). Different procedures including polarisation and cyclic voltammetry in acid or base solutions have been used to activate the glassy carbon electrodes. The electrochemical behaviours of 3,4-DHBA on these activated electrodes were studied and compared. Experimental results showed that the glassy carbon electrode polarised in H2SO4 (AGCE-P/H2SO4) has the greatest sensitivity and reproducibility to 3,4-DHBA. 3,4-DHBA performed a linear relationship from 1.0 × 10−7 to 1.0 × 10−4 M on the AGCE-P/H2SO4. The detection limit was down to 6.2 × 10−8 M. This method has been successfully applied for the detection of hydroxyl radical levels in atmosphere without separation and purification process.

Constructing a Sensitive Electrochemical Sensor for Tyrosine Based on Graphene Oxide-ɛ-MnO2 Microspheres/Chitosan Modified Activated Glassy Carbon Electrode

In present study, novel graphene oxide (GO)-ɛ-MnO2 microspheres with homogeneous flaky texture were synthesized by a precursor conversion method and bound to activated glassy carbon electrodes (GCE) by using chitosan (CS), a fixing agent, to fabricate a facile and sensitive electrochemical sensor for the determination of tyrosine (Tyr). Adding the electrochemical pretreatment to glassy carbon electrode was conducive to the increase of surface concentrations of C-O functional groups and generating rough surface on the modified electrode, thus improving the electrochemical performance compared with that of untreated glassy carbon electrode. The proposed electrochemical sensor exhibited high sensing performance toward Tyr. Scanning electron microscopy showed that GO-ɛ-MnO2 microspheres were well mixed with CS and well dispersed on the modified electrode surface, with uniform morphology and size distribution. The experimental conditions were optimized, under which the sensor showed a linear proportional response to Tyr in a wide determination range from 0.02 to 20.0 μM with a detection limit (S/N = 3) of 8.3 nM. Moreover, GO-ɛ-MnO2 microspheres/CS/activated GCE was successfully applied to detect Tyr in milk samples and real dried blood spots samples, giving satisfactory results.

Sensitive and Validated Voltammetric Methods for Determination of Zileuton in Serum, Urine and Pharmaceutical Dosage Forms at Activated Glassy Carbon Electrode

Sensitive and Validated Voltammetric Methods for Determination of Zileuton in Serum, Urine and Pharmaceutical Dosage Forms at Activated Glassy Carbon Electrode

Fast Electrocatalytic Determination of Methimazole at an Activated Glassy Carbon Electrode.

A fast and simple voltammetric method for the determination of methimazole in pharmaceutical products was reported. A glassy carbon electrode was pretreated by anodization at +1.75 V (vs. SCE) for 5 min, followed by potential cycling in the range of 0.3-1.3 V (20 cycles). The pretreated electrode showed an excellent electrocatalytic effect on the oxidation of methimazole. Compared with untreated electrode, a large decrease (~300 mV) in the oxidation peak of methimazole was observed. The oxidation peak current at the new potential (0.4 V vs. SCE) was linearly dependent on the concentration of methimazole in the range of 7.0 - 130 μM with a detection limit of 3.7 μM (S/N = 3). The method was successfully used in the determination of methimazole in thyramozol tablets. Due to the simple and fast electrode preparation, there is no need for electrode cleaning or storage.

Highly Sensitive and Simultaneous Determination of Hydroquinone and Catechol at an Optimized Activated Glassy Carbon Electrode

Glassy carbon electrode (GCE) was activated with four different electrochemical activation process: (1) by applying a fixed potential of +1.7 V for 400 s (FP-AGC); (2) by cycling the potential between +2.0 and −0.3V for 15 cycles at 0.1 V/s (CP-AGC); (3) by applying a fixed potential of +1.7 V for 400 s followed by cycling the potential between +2.0 and −0.3V for 15 cycles at 0.1 V/s (FC-AGC) and (4) by applying +1.7 V for 400s followed by -1.0 V for 60s (DP-AGC). All four activated GCEs showed catalytic activity and reversibility toward the oxidation of both hydroquinone (HQ) and catechol (CT) in 0.1 M phosphate buffer solution (PBS, pH 7.0). However, a remarkable signal enhancement of HQ and CT was obtained at DP-AGC, which is considered as optimized activated GC. By using this optimized AGC we have developed a highly sensitive and selective electrochemical method for the determination of HQ and CT simultaneously. The redox responses from the mixture of HQ and CT were easily resolved at DP-AGC. The detection limits for HQ and CT were calculated to be 15.0 and 10.0 nM respectively. The optimized AGC was successfully examined for real sample analysis with tap water and it showed a stable and reliable recovery data with reproducibility.

Fabrication of Nickel Tetrasulfonated Phthalocyanine Functionalized Multiwalled Carbon Nanotubes on Activated Glassy Carbon Electrode for the Detection of Dopamine

AbstractThe nickel tetrasulfonated phthalocyanine (NiTsPc) functionalized multiwalled carbon nanotube (MWCNT) nanocomposite was prepared by a simple sonochemical method. Here, NiTsPc served as a dispersing agent for MWCNT via ππ interaction between MWCNT and NiTsPc. The activated glassy carbon electrode (AGCE) modified with MWCNT‐NiTsPc composite exhibited a good electrocatalytic ability toward dopamine and displayed a good linear dependence in the concentration range of 20 nM–1.384 mM with a sensitivity of 0.17 µA µM−1 cm−2. The detection limit is 1 nM based on the signal‐to‐noise ratio of 3.