Modified Pencil Graphite Electrode Research Articles

A Self-Powered Enzymatic Glucose Sensor Utilizing Bimetallic Nanoparticle Composites Modified Pencil Graphite Electrodes as Cathode.

Enzymatic biofuel cells (EBFC) are promising sources of green energy owing to the benefits of using renewable biofuels, eco-friendly biocatalysts, and moderate operating conditions. In this study, a simple and effective EBFC was presented using an enzymatic composite material-based anode and a nonenzymatic bimetallic nanoparticle-based cathode respectively. The anode was constructed from a glassy carbon electrode (GCE) modified with a multi-walled carbon nanotube (MWCNT) and ferrocene (Fc) as a conductive layer coupled with the enzyme glucose oxidase (GOx) as a sensitive detection layer for glucose. A chitosan layer was also applied to the electrode as a protective layer to complete the composite anode. Chronoamperometry (CA) results show that the MWCNT-Fc-GOx/GCE electrode has a linear relationship between current and glucose concentration, which varied from 1 to 10mM. The LOD and LOQ were calculated for anode as 0.26mM and 0.87mM glucose, respectively. Also the sensitivity of the proposed sensor was calculated as 25.71 A/mM. Moreover, the studies of some potential interferants show that there is no significant interference for anode in the determination of glucose except ascorbic acid (AA), uric acid (UA), and dopamine (DA). On the other hand, the cathode consisted of a disposable pencil graphite electrode (PGE) modified with platinum-palladium bimetallic nanoparticles (Nps) which exhibit excellent conductivity and electron transfer rate for the oxygen reduction reaction (ORR). The constructed EBFC was optimized and characterized using various electroanalytical techniques. The EBFC consisting of MWCNT-Fc-GOx/GCE anode and Pt-PdNps/PGE cathode exhibits an open circuit potential of 285.0mV and a maximum power density of 32.25µWcm-2 under optimized conditions. The results show that the proposed EBFC consisting of an enzymatic composite-based anode and bimetallic nanozyme-based cathode is a unique design and a promising candidate for detecting glucose while harvesting power from glucose-containing natural or artificial fluids.

Electrochemical biosensing of Acinetobacter baumannii gene using chitosan-gold composite modified electrode

In this study, a novel electrochemical biosensor was developed for the sensitive and selective detection of the Acinetobacter baumannii gene sequence. The biosensor was created by immobilizing a capture probe specific to the A. baumannii gene on the surface of chitosan-gold modified pencil graphite electrodes. Following solid-state hybridization on the Chit-Au/PGE surface, the target DNA sequence of the A. baumannii was detected by measuring the guanine signal using square wave voltammetry (SWV). All experimental parameters impacting sensor response are examined in order to improve hybridization efficacy, and the electrochemical biosensor's performance. The limit of detection (LOD) for the A. baumannii gene sequence was calculated and found to be 1.93 nM. Three different non-complementary DNA sequences were used to evaluate the assay selectivity, but no interference effect was obtained. Additionally, the potential applicability of the biosensor to real samples was tested in artificial serum media. The suggested electrochemical test procedure is simple, approachable, and quick, making it a convenient approach for the screening of DNA sequence.

Low-cost immunosensing approach for Chagas disease: exploiting modified pencil graphite electrodes with polymer films

Low-cost immunosensing approach for Chagas disease: exploiting modified pencil graphite electrodes with polymer films

Fabrication of an amperometric urea biosensor based on chitosan modified pencil graphite electrode

An amperometric biosensor was fabricated by using urease enzyme, graphene oxide (GO), gold nanoparticles (AuNPs) and chitosan (CHIT) composite. Pencil graphite electrode (PGE) was used for the electrodeposition of nanomaterials and the detection of urea. Various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier-transform infrared (FTIR) spectra, UV–visible spectroscopy, zeta-potential and cyclic voltammetry (CV) were used for characterization. The biosensor showed an optimum response at pH 8.0 and 40 °C temperature. The maximum current of the proposed biosensor was due to electron generated at 0.79 V against Ag/AgCl electrode. Fabricated biosensor showed a wide linear range (0.1–1.0 mg/mL) and low limit of detection (0.9956 mg/mL) with satisfactory selectivity, sensitivity (0.00555 μA/mg/mL/cm2), and stability. It was successfully employed for detecting urea concentration in sera samples of healthy individuals and patients with kidney disorders.

Glycine-modified Pencil Graphite Electrode as a Sensor for Caffeine Determination: A Voltammetric Study

Background: Caffeine (CAF) is a widely used chemical in foods and pharmaceuticals that is consumed by a lot of people every day. Overconsumption of caffeine can lead to some undesirable symptoms. However, CAF is considered a crucial nervous system stimulant. Aims: This study aimed to find an accurate and effective route for determining caffeine using voltammetric techniques. Objective: In this work, for the first time, a glycine (Gly) modified pencil graphite electrode (Gly/PGE) was used for the determination of caffeine (CAF) by Square Wave Adsorptive Stripping Voltammetry (SWAdSV) technique. Methods: The modification procedure of PGE by Gly was accomplished by performing the cyclic voltammetry (CV) technique for 10 cycles at a potential range of 0.8 to 1.8 V. Moreover, the characterization of Gly/PGE was done by applying the CV technique in aqueous and non-aqueous media and electrochemical impedance spectroscopy (EIS) in addition to the SEM technique. The movement type of CAF toward Gly/PGE was proven to be a diffusion-controlled process by conducting some measurements at different scan rates. The supporting electrolyte for the determination of CAF was studied, where 100 mM of sulfuric acid (H2SO4) provided the best result. Optimization of accumulation time, pulse size, and wave frequency were implemented and found to be 60 s accumulation time, 50 mV pulse size, and 25 Hz wave frequency. The stability of Gly/PGE was studied in different mediums, such as air, ultrapure water, and acetonitrile (CH3CN). Results: The determination of CAF under optimum conditions was within the linear concentration range of 0.1–75 μM, with a correlation coefficient of R2 = 0.9990. The limit of detection (LOD) and limit of quantification (LOQ) were 0.070 and 0.231 μM, respectively. Conclusion: An effective voltammetric methodology was suggested to determine CAF. This methodology has great promise to be applied in different matrices to determine CAF.

Unprecedented and laborless polymer film of azorubin S for electrocatalytic sensing of nicotine in human serum and saliva

AbstractAn accurate, disposable and cost‐effective determination, and monitoring of nicotine in human bodily fluids such as serum and saliva is significant due to the deleterious effects on humankind. In this paper, it was reported an electrocatalytic sensing platform for nicotine determination with poly azorubin s film modified pencil graphite electrode qualified by electroanalytical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy, electron beam based technique of scanning electron microscopy, and X‐ray based techniques including photoelectron spectroscopy and energy dispersive spectroscopy. The developed platform exhibited a 410 % signal increase compared to the bare pencil graphite electrode (280 % increase in current density over aPGE) for nicotine detection due to the improved charge transfer and conductivity characteristics of the polymer film. The oxidation peak at 700 mV was employed for nicotine detection with a good detection sensitivity of , a remarkable detection limit of 89 nM, and wide linear ranges of 0.25–3 μM and 5–100 μM. Furthermore, the electrochemical sensor showcases superb stability, selectivity and accuracy for the determination of nicotine in real samples of human serum and saliva.

Electrochemical DNA-nano biosensor for the detection of Goserelin as anticancer drug using modified pencil graphite electrode.

Goserelin is an effective anticancer drug, but naturally causes several side effects. Hence the determination of this drug in biological samples, plays a key role in evaluating its effects and side effects. The current studies have concentrated on monitoring Goserelin using an easy and quick DNA biosensor for the first time. In this study, copper(II) oxide nanoparticles were created upon the surface of multiwalled carbon nanotubes (CuO/MWCNTs) as a conducting mediator. The modified pencil graphite electrode (ds-DNA/PA/CuO/MWCNTs/PGE) has been modified with the help of polyaniline (PA), ds-DNA, and CuO/MWCNTs nanocomposite. Additionally, the issue with the bio-electroanalytical guanine oxidation signal in relation to ds-DNA at the surface of PA/CuO/MWCNTs/PGE has been examined to determination Goserelin for the first time. It also, established a strong conductive condition to determination Goserelin in nanomolar concentration. Thus, Goserelin's determining, however, has a 0.21 nM detection limit and a 1.0 nM-110.0 µM linear dynamic range according to differential pulse voltammograms (DPV) of ds-DNA/PA/CuO/MWCNTs/PGE. Furthermore, the molecular docking investigation highlighted that Goserelin is able to bind ds-DNA preferentially and supported the findings of the experiments. The determining of Goserelin in real samples has been effectively accomplished in the last phase using ds-DNA/PA/CuO/MWCNTs/PGE.

Ultra-thrifty/cost-effective approach to determine Alizarin Red S (ARS) in natural water supplies through ruthenium-cobalt modified pencil graphite as minuscule electrode

ABSTRACT Herein, we present an extremely cost-effective approach to analyse and evaluate the fabric dye Alizarin red-S (ARS), one of the critical water pollutants. Moreover, this work shows an interesting and a one-step budget friendly promising electrochemical route for valorising ruthenium-cobalt bimetallic nanoparticles fabricated on graphene-chitosan modified pencil graphite electrode (RuNPs@CoNPs/Gr-Chi/PGE) in determining ARS in phosphate buffered saline (PBS) of pH −3 at the minute level. To analyse and evaluate the morphology of the sensor, we leveraged X-ray diffraction techniques, Scanning electron microscopy, and energy-dispersive X-ray analysis. Using (SWV)Square wave voltammetry, under the optimised experimental conditions, the response currents of the composite electrode exhibited a wide linearity of 2.5 µM to 2550 µM with an LOD and LOQ of 0.277 µM and 0.839 µM respectively. The composite exhibited promising results concerning stability over five weeks further focusing on the electrode’s reliability. It is validated in tap water, Buckingham Canal water, and textile water for the assay of ARS.

Voltammetric performance of nanofiber structured over-oxidized poly(3,4-ethylenedioxythiophene) modified pencil graphite electrodes for dobutamine sensing

A modified electrode was developed for the electrochemical sensing of dobutamine (DBT), one of the catecholamines. For this modification process, pencil graphite electrodes (PGE) were modified with over-oxidized nanofiber structured poly (3,4-ethylenedioxythiophene) (PGE/OPEDOTNF) by electropolymerization. The electrochemical performance of PGE/OPEDOTNF was evaluated by cyclic and differential pulse voltammetry. In addition, the performances of non-nanofiber PEDOT-modified PGE electrodes were also examined for comparison. The characterization of the modified electrodes was carried out by scanning electron microscopy and electrochemical methods. The signal of the modified electrodes was observed in a linear range of 0.1-2.0 µM against DBT using the differential pulse voltammetry method. The limit of detection and quantification are calculated as 0.026 µM and 0.086 µM, respectively. The effect of the interfering species was examined. It has been shown that DBT can be detected sensitively and selectively using pencil graphite electrodes modified with nanofiber-structured poly(3,4-ethylenedioxythiophene). The repeatability of PGE/OPEDOTNF electrodes was found to be 5.2%. PGE/OPEDOTNF electrodes remained stable for 15 days without losing their electrochemical activity.

Development of simple and effective poly methyl orange modified pencil graphite electrode for the voltammentric investigation of aminotriazole in presence of 2,4-dichlorophenoxyacetic acid

The growing health risks linked to environmental exposure to mutagenic, teratogenic, and carcinogenic herbicides have sparked a significant interest in developing rapid and cost-effective detection technologies for accurate quantification of these compounds. Therefore, current research concerns a selective and sensitive electrochemical determination of Aminotriazole (AMT) using an inexpensive modified polymerized methyl orange pencil graphite electrode (PMO/PGE). The PMO/PGE and bare pencil graphite electrode (BPGE) have been characterized through various analytical techniques such as scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and electrochemical impedance spectroscopy (EIS). The electro-oxidation behavior of AMT was investigated by utilizing various methodologies including cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) in 0.1 M phosphate buffer solution (PBS) of pH 7.0. AMT exhibits a significant increase in anodic peak current of 7.15 µA at PMO/PGE compared to BPGE. The effect of electro-kinetic factors involved in the electro-oxidation of AMT, such as the heterogeneous rate constant, scan rate, surface concentration, pH and the number of electrons and protons transferred were resolved. The electro-oxidation reaction involves two protons and two electrons, according to the electrochemical analysis of AMT at PMO/PGE. The number of electrons involved in a redox reaction is often determined experimentally, and it is a key parameter in understanding the reaction mechanism. Under the investigational conditions, the anodic peak current of the analyte is directly proportional to its concentration in the range 1.0 – 13.0 µM with the limit of detection (LOD) being 1.24 × 10−8 M. The developed modifiedsensor has got good reproducibility, sensitivity, selectivity and stability, and it could be successfully validated for the detection of AMT present in real samples.

A novel molecularly rabeprazole imprinted electrochemical sensor based on Fe3O4@SiO2–MWNTs nanocomposite

A sensitive and selective electrochemical sensor was designed for rabeprazole (RAB) detection using a molecularly imprinting polymer (MIP) modified with Fe3O4@SiO2–MWNTs nanocomposite. Calculation methods were utilized to determine the best monomer and also to check the geometry of the optimized RAB molecule and RAB-PY complex. To obtain the maximum extraction recovery of RAB, the influence of various parameters was investigated and experimental settings were optimized with two multivariable optimization methods of Placket–Burman design (PBD) and central composite design (CCD). Cyclic voltammetry (CV) was used to synthesis the polypyrrole film on a modified pencil graphite electrode (PGE). Analyte extraction from the polymer film and all quantitative measurements were performed by differential pulse voltammetry (DPV). The morphology and characteristics of Fe3O4@SiO2–MWNTs nanocomposite, the modified electrode surface, and also the synthesized sensor surface was investigated with field emission scanning electron microscope (FESEM) coupled to an energy dispersive x-ray (EDX). In optimal conditions, the modified sensor depicted desirable figures of merit of a limit of detection (LOD) of 0.035 μM (S/N = 3), a limit of quantitation (LOQ) of 0.15 μM (S/N = 10), and a linear detection range from 5 to 500 μM. Moreover, the MIP–Fe3O4@SiO2–MWNTs − PGE sensor was showed acceptable repeatability (RSD value of 4.18 %), reproducibility (RSD value of 5.53 %), and stability (reusability) up to one month (92 %). The proposed method was employed for preconcentration and extraction of rabeprazole in pharmaceutical and biological samples, successfully.

An eco-friendly electrochemical approach for determination of sunset yellow at a Co3O4@biochar modified pencil graphite electrode

The quantitative detection of food additives represented by sunset yellow is of great significance to food safety. In this study, a simple electrochemical strategy was proposed for the accurate detection...

Electrochemical investigation of an anticancer drug 5-Fluorouracil in the presence of Theophylline using low-cost and disposable poly(GLY) modified pencil graphite electrode

Herein this study, a facile, efficient and disposable electrochemical sensor has been prepared by electropolymerization of glycine (poly(GLY)) on the surface of pencil graphite electrode (PGE). The surface topology of the equipped poly(GLY) modified pencil graphite electrode (poly(GLY)/PGE) and bare pencil graphite electrode (BPGE) has been characterized by the scanning electron microscopy (SEM) combined with energy dispersive x-ray analysis (EDX) and charge transfer behaviour was measured by electron impedance spectroscopy (EIS) method. The voltammetric behaviour of anticancer, 5-fluorouracil (5-FU) in the presence of theophylline (THP) has been carried out in 0.1 M phosphate buffer solution (PBS) of physiological pH 7.0 using different techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The proposed poly(GLY)/PGE shows augmented peak current for 5-FU at lower potential side over the BPGE due to the electrocatalytic behaviour of modifier layers wrapped on the electrode surface. The kinetic behaviour of 5-FU at modified electrode surface was studied by varying different parameters such as pH, scan rate and concentration study in 0.1 M PBS used as a supporting electrolyte. The limit of detection (LOD) for 5-FU was attained using DPV method with different concentrations (1.0–13.0 μM) and it was found to be 0.012 μM. The possible electrochemical reaction of 5-FU was proposed and it was incorporated by two electrons and two protons mechanism at modified electrode surface. The voltammetric response of poly(GLY)/PGE towards the determination of 5-FU was unaffected in the presence of some excipients in addition to the remarkable stability and reproducibility. The applicability of the proposed sensor has been performed by real sample investigation of 5-FU with a substantial percentage of recovery results in all optimized conditions.

Electrochemical determination of insensitive munition constituents 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) using gold nanoparticle/carbon nanotube‐modified pencil graphite electrode in groundwater sample

AbstractFor the electrochemical detection of nitrotriazolone (NTO), multiwalled carbon nanotubes (MWCNT) and gold nanoparticles have been combined to generate nanocomposites. Electrochemical analysis and surface characterisation using scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) spectroscopy techniques were used to confirm the presence of gold nanoparticles on MWCNT. The electrochemical behavior of NTO at the modified pencil graphite electrode in the pH range of 2.0–10.0 (0.04 M Britton‐Robinson buffer solution) was evaluated using cyclic (CV) and differential pulse voltammetry (DPV).The suggested electrochemical sensor displayed a quick reaction to NTO with an optimal set of experimental parameters, a linear calibration curve spanning 30 to 1500 nM, and a detection limit of 22.6 nM. Using the differential pulse voltammetry technique, the usefulness of the MWCNT/AuNPs, and PGE for the determination of NTO in groundwater was evaluated.

Voltammetric Determination of Acrylamide Using Coal Tar Pitch Modified Pencil Graphite Electrode by SWV

Voltammetric Determination of Acrylamide Using Coal Tar Pitch Modified Pencil Graphite Electrode by SWV

A disposable voltammetric sensor for the determination of diphenylamine using modified pencil graphite electrode.

This study reports the electrochemical monitoring and sensing of diphenylamine (DPA), an anti-scald agent on a modified pencil graphite electrode (PGE). DPA is also a potentially toxic environmental pollutant. A polymer of tyrosine synthesized by electrochemical process was utilized for the determination of DPA in real samples. The electrodes were characterized using IR, SEM, EDAX, AFM and EIS analyses. As far as we know, this is first time reporting the utilization of modified PGE via green approach for the monitoring of DPA. A dynamic linear range of 1.00-117.11µM with a lower detection limit (LOD) of 0.7050µM was showed by this sensor for the electrochemical quantification of DPA. The electrochemical oxidation of DPA on the modified sensor followed a mixed adsorption -diffusion controlled kinetics. The sensor also showed good anti-interference property for the determination of DPA in real samples. Furthermore, the developed sensor was applied for the selective sensing of DPA from real apple extracts with good recovery. The real sample analysis was validated with standard spectrophotometric method.

Conductive PEDOT:PSS copolymer electrode coatings for selective detection of dopamine in ex vivo mouse brain slices

A novel voltammetric sensor was developed to selectively determine dopamine (DA) concentration in the presence of ascorbic acid (AA) and 3,4-dihydroxyphenylacetic acid (DOPAC). This sensor utilizes a modified pencil graphite electrode (PGE) coated with a newly synthesized poly (3,4-ethylene dioxythiophene) (PEDOT):poly (styrene sulfonate-co-2-(3-(6-Methyl-4-oxo-1,4-dihydropyrimidin-2-yl) ureido) ethyl methacrylate) (P(SS-co-UPyMA)) composite. The PEDOT:P(SS-co-UPyMA) (PPU) composite was characterized using nuclear magnetic resonance, X-ray photoelectron, and Raman spectroscopies. The PPU-coated PGE was characterized using electrochemical techniques, including cyclic and differential pulse voltammetry. Compared to uncoated, PPU-coated PGE demonstrated improved sensitivity and selectivity for DA. The sensor exhibited a dynamic linear range of 0.1–300 μM for DA, with a detection limit of 44.4 nM (S/N = 3). Additionally, the PPU-coated PGE showed high reproducibility and storage stability for four weeks. To demonstrate its practical applicability, the PPU-coated PGE sensor was used for ex vivo brain slice samples from control and Parkinson's disease model mice.

Electrocatalytic Determination of Uric Acid with the Poly(Tartrazine)-Modified Pencil Graphite Electrode in Human Serum and Artificial Urine.

A novel electrocatalytic sensing strategy was built for uric acid (UA) determination with an exceptionally developed poly(tartrazine)-modified activated pencil graphite electrode (pTRT/aPGE) in human serum and artificial urine. The oxidation signal of UA at 275 mV in pH 7.5 phosphate buffer solution served as the analytical response. Cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the sensing platform, which was able to detect 0.10 μM of UA in the ranges of 0.34-60 and 70-140 μM. The samples of human serum and artificial urine were analyzed by both the pTRT/aPGE and the uricase-modified screen-printed electrode. The results were statistically evaluated and compared with each other within the confidence level of 95%, and no significant difference between the results was found.

Development of a Disposable Pencil Graphite Electrode Modified with Poly 1,5-Diaminonaphthalene for Voltammetric Determination of Flufenamic Acid

Due to their comparable electrical properties, pencil graphite electrodes (PGE) have become a more popular electrode in electrochemical applications than traditional carbon electrodes, mostly because of their affordability and availability, which allows for disposable applications. Both cyclic voltammetry (CV) and chronoamperometry (CA) techniques were used to develop a new disposable modified pencil graphite electrode based on the electropolymerization of 1,5-diaminonaphthalane (1,5-DAN). Characterization results confirmed that the modified p-1,5-DAN/PGE(CV) sensor showed much enhanced sensitivity and lower resistivity than the bare and p-1,5-DAN/PGE(CA) sensor, therefore, it was used for the sensitive and selective voltammetric determination of flufenamic acid (FFA). Under the optimum experimental conditions, the p-1,5-DAN/PGE(CV) sensor showed limits of detection (LOD) and quantitation (LOQ) of 4.97 × 10−10 (0.14 ng ml−1) and 1.66 × 10−9 M (0.47 ng ml−1), respectively, applying square wave anodic stripping voltammetry method. The p-1,5-DAN/PGE(CV) sensor also exhibits good accuracy, repeatability, storage stability and selectivity for detecting FFA in biological fluids. These results confirms that the developed p-1,5-DAN/PGE(CV) sensor is more sensitive to measuring FFA in biological fluids, pharmaceutical formulations, and pharmacokinetic studies compared with the previous electrochemical sensors.

Atomic layer deposited zinc oxide thin film on pencil graphite for DNA sensor applications

Atomic Layer Deposition (ALD) enables precise thin-film deposition on electrode substrates for electrochemical sensors. In this work, we present the first example of ALD grown zinc oxide (ZnO) deposition on pencil graphite surfaces for deoxyribonucleic acid (DNA) sensory applications, including its detection and DNA damage investigation. For DNA sensing studies, the use of highly productive materials is essential. In this context, the ZnO modified pencil graphite electrodes (ZnO/PGEs) exhibited good electrochemical properties that make them a suitable substrate. ZnO films were characterized using scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. The DNA recognition capability of the thin film coated electrodes was tested by using differential pulse voltammetry (DPV), which showed a linear response ranging from 1 mg L−1 to 200 mg L−1 based on the oxidation of guanine (G) with a limit of detection value (LOD) of 0.53 mg L−1 (n = 3). In addition to this, impedimetric monitoring of oxidative DNA damage was performed in the presence of copper(II)/hydrogen peroxide (Cu(II)/H2O2) reagents, and protection studies were conducted in the presence of ascorbic acid. ZnO thin film-based electrodes exhibited good sensor performance in terms of sensitivity, stability, and reproducibility.