Modified Carbon Nanotube Paste Electrode Research Articles

Ferrocene-Containing Gallic Acid-Derivative Modified Carbon-Nanotube Electrodes for the Fast Simultaneous and Selective Determination of Cytostatics from Aqueous Solutions

In this work, a ferrocene-containing gallic acid-derivative modified carbon-nanotube paste electrode (Gal-Fc-CNT), obtained through simple mechanical mixing, was studied for the fast simultaneous voltammetric determination of doxorubicin (DOX), capecitabine (CPB), and cyclophosphamide (CPP) as cytostatic indices based on their cumulative signals and the selective determination of DOX. The individual and simultaneous electrochemical behavior of DOX, CPB, and CPP, studied through cyclic voltammetry (CV) on the Gal-Fc-CNT paste electrode at various pHs and potential ranges, allowed for the development of a simple simultaneous determination method as a cytostatic index at a pH of 12 using square-wave voltammetry, which allowed for a better performance than reported electrodes for each individual cytostatic. A faster and selective detection of DOX, with a limit of detection of 75 ng·L−1, was achieved using square-wave voltammetry at a pH of 3. The good results obtained for the real tap water assessment indicated the applicability of the Gal-Fc-CNT paste electrode for practical applications (water samples).

Electrochemical Analysis of the Antihistamine Drug Cetirizine at a Poly(Glutamine) Modified Carbon Nanotube Paste Electrode

AbstractAn inexpensive and efficient sensor was developed for the electrochemical analysis of the antihistamine drug cetirizine (CTZ). The active sites on the bare carbon nanotube paste electrode surface were improved by the electropolymerization of poly(Glutamine). This modified electrode enhances the electrochemical response of the examining molecule. The study was conducted using a cyclic voltammetry technique in phosphate buffer saline of physiological pH 7.0 at a scan rate of 0.1 V/s. The developed electrode possesses increased conductance and declined overpotential for the determination of CTZ. At the optimized conditions, the detection limit was evaluated by obtaining the current response of CTZ at the varied concentration, and it was obtained as 0.12 μM. The poly glutamine modified carbon nanotube paste electrode was successfully applied to determine CTZ in tablet and human urine samples with acceptable recovery.

Electrochemical determination of zinc(II) using N1-hydroxy-N1,N2-diphenylbenzamidine and multi-walled carbon nanotubes modified carbon paste electrode

In this study, a new carbon paste electrode modified with a laboratory-synthesized ligand, N1-hydroxy-N1,N2-diphenylbenzamidine (HDPBA) and multi-walled carbon nanotubes (MWCNTs) (HDPBA‒MWCNTs/CPE) has been developed. The modified electrode was applied for preconcentration and voltammetric determination of zinc ions (Zn(II)) by square wave anodic stripping voltammetry (SWASV). The preconcentration of Zn(II) on the electrode surface was performed in 0.1 M Brinton Robinson (B–R) buffer solution (pH 6) at an applied potential of −1.30 V versus Ag/AgCl for 120 s, followed by stripping in the positive potential scan of the SWASV after a quit time of 10 s. Under optimized experimental conditions, the proposed electrode exhibited a wider linear dynamic response for Zn(II) in a concentration range of 0.02–10.00 μM with a detection limit of 2.48 nM. This is due to the excellent metal-chelation property of the ligand, and the good conductivity and large surface area of MWCNTs which significantly improved the sensing performance of the nanocomposite modified electrode. The selectivity of the electrode was studied by evaluating the interference effects of various foreign ions on the peak current of Zn(II). The method exhibited high reproducibility with a relative standard deviation (RSD) of 3.1%. The present method was applied for the determination of zinc ions in water samples. The recovery values in the tested samples were found to be 98.50–106.0%, indicating a good accuracy of the proposed electrode. Furthermore, the electrochemical behavior of HDPBA in acetonitrile and aqueous solutions has been studied.

Electrochemical detection and quantification of catechol based on a simple and sensitive poly(riboflavin) modified carbon nanotube paste electrode

In the present research work, selective and sensitive catechol (CT) detection and quantification were shown in the presence of resorcinol (RS) in 0.2 M phosphate buffer (PB) solution by preparing a low-cost, simple, and green carbon nanotube paste electrode (CNTPE) surface activated with electropolymerized riboflavin (PRF). The morphological, conductivity, and electrochemical features of the modified electrode (PRFMCNTPE) and bare carbon nanotube paste electrode (BCNTPE) materials were analyzed using electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The PRF-activated electrode displays outstanding sensitivity, stability, selectivity, reproducibility, and repeatability for the redox feature of CT with improved electrochemical current and declined electrochemical potential compared to BCNTPE. The peak currents of CT are correlated to the different CT concentrations (CV method: 6.0–60.0 μM & DPV method: 0.5–7.0 μM), and the obtained detection limit (DL) and quantification limit (QL) are found to be 0.025 μM and 0.085 μM (CV method) and 0.0039 μM and 0.0132 μM (DPV method), respectively. The prepared PRFMCNTPE material was advantageous for the examination of CT in environmentally important tap water sample as a real-time application.

Electroanalytical Detection of Indigo Carmine in Presence of Tartrazine Using a Poly(dl-phenylalanine) Modified Carbon Nanotube Paste Electrode

Certain dyes are deleterious to the biological system, including animals and plants living in the water sources, soil sources, and so on. Thus, the analysis of these dyes requires a potent, quick, and cost-effective approach to the environmental samples. The present research work shows a modest, low-cost, and eco-friendly electrochemical device based on poly(dl-phenylalanine)-layered carbon nanotube paste electrode (P(PAN)LCNTPE) material for indigo carmine (ICN) detection in the presence of tartrazine. The cyclic voltammetric, field emission scanning electron microscopy, and electrochemical impedance spectroscopic methods were operated for the detection of the redox nature of ICN and electrode material surface activities, respectively. In better operational circumstances, P(PAN)LCNTPE provided better catalytic activity for the redox action of ICN than the bare carbon nanotube paste electrode. The P(PAN)LCNTPE showed good electrochemical activity during the variation of ICN concentrations ranging from 0.2 µM to 10.0 µM with improved peak current, and the limit of detection was about 0.0216 µM. Moreover, the P(PAN)LCNTPE material was performed as a sensor of ICN in a tap water sample and shows adequate stability, repeatability, and reproducibility.

Electrocatalytic Determination of Hydroxychloroquine Using Sodium Dodecyl Sulphate Modified Carbon Nanotube Paste Electrode.

Selective, sensitive, easy, and fast voltammetric techniques were developed for the analysis of Hydroxychloroquine (HCQ). These analysis were carried out at sodium dodecyl sulphate modified carbon nanotube paste electrode (SDSMCNTPE) using an aqueous 0.2 M phosphate buffer solution as supporting electrolyte. The field emission-scanning electron microscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy were used for material characterization. A minute quantity of the SDS surfactant was sufficient to convey an outstanding electrocatalytic action to the electrochemical oxidation nature of HCQ. The HCQ molecule parades only electrochemical oxidation (irreversible) with the transfer of two electrons. The detection of HCQ was carried out through CV method at SDSMCNTPE and bare carbon nanotube paste electrode (BCNTPE). The corresponding analytical curve offered a decent linear nature in the considered HCQ concentration range (10–40 µM) and the detection limit was found to be 0.85 µM. The significant peak to peak split-up was observed between HCQ and interferents with a decent sensitivity and stability. The SDSMCNTPE to be an approachable electrode for the usage in the examination of HCQ independently and in the presence of paracetamol (PC) and ascorbic acid (AA). Thus, they were used to determine HCQ in pharmaceutical formulations and the results that showed good agreement with comparative methods. Furthermore, a mechanism for HCQ electro-oxidation was proposed.

Selective determination of Cr(III) by modified carbon nanotube paste electrode: a potentiometric study

AbstractBACKGROUNDPotentiometric detections based on ion‐selective electrodes offer the advantages of simplicity, speed, and low cost over other electrochemical methods. In this work, the preparation of a novel carbon‐paste electrochemical sensor containing the synthesized N‐(1‐(4‐bromophenyl)‐3‐oxo‐3‐phenylpropyl)acetamide is described. Multi‐walled carbon nanotubes (MWCNTs) were incorporated into the electrode composition to promote electron transfer reactions. The modified carbon paste electrode was evaluated as a selective sensor for the detection of chromium (III).RESULTSThe prepared sensor showed nearly stable potentials in the pH range of 4.0–6.5, with a fast response time (<15 s). At the optimum conditions, the potentiometric method exhibited a linear response toward Cr(III) concentration in the range of 5.0 × 10−7 to 1.0 × 10−3 mol L−1 with a Nernstian slope of 19.5 ± 0.1 mV per decade and a detection limit of 3.1 × 10−7 mol L−1.CONCLUSIONThe proposed sensor possesses the advantages of good selectivity to Cr(III) and an improved detection limit compared to the results of some other studies. Better selectivity can be attributed to the ability of the ionophore to form a stable chelate with Cr(III) ions. The new Cr(III) sensor showed excellent stability over 8 weeks and its response time was comparable to other previously reported chromium ion‐selective electrodes (ISEs) . The simple, fast, and cheap synthesis method of ionophore provided other advantages for this study. The modified electrode was also used as a sensor for the end‐point detection in the potentiometric titration of Cr(III) against ethylenediaminetetra acetic acid (EDTA). © 2021 Society of Chemical Industry (SCI).

Construction and application of highly sensitive spinel nanocrystalline zinc chromite decorated multiwalled carbon nanotube modified carbon paste electrode (ZnCr2O4@MWCNTs/CPE) for electrochemical determination of alogliptin benzoate in bulk and its dosage form: green chemistry assessment.

A new sensor for alogliptin benzoate (ALG) estimation based on a simple and sensitive method was evolved on multiwalled-carbon-nanotube modified nanocrystalline zinc chromite carbon paste electrodes (ZnCr2O4@MWCNTs/CPEs). ALG electrochemical behavior was evaluated using a cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry (CA). The new electrode materials were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDX) for elemental analysis and mapping, and X-ray diffraction (XRD) and the X-ray photoelectron spectroscopy (XPS) measurements. All these measurements exhibiting enhanced activity and high conductivity compared to the bare electrode without modification. The calibration curves obtained for ALG were in the ranges of 0.1–20 μmol L−1 with a quantification and detection limits of 0.09 and 0.03 μmol L−1, respectively. The prepared sensor showed a good sensitivity and selectivity with less over potential for ALG determination. Finally, the presented method was successfully applied as a simple, precise and selective electrochemical electrode for the estimation of ALG in its pharmaceutical dosage form.

MgO and MWCNTs amplified electrochemical sensor for guanine, adenine and epinephrine

In the present study, magnesium oxide and multi-walled carbon nanotubes modified carbon paste electrode (MgO-MWCNTs-MCPE) utilized for specific and simultaneous investigation of guanine (GA), adenine (AD) and epinephrine (EP). The MgO nanoparticles (NPs) was prepared by mechanochemical manner. Particle size, surface morphology and elemental analysis of MgO NPs was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy with energy dispersive X-ray (FESEM- EDX). The electrochemical deeds of the GA, AD and EP were studied by cyclic voltammetry (CV), Linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) at MgO-MWCNTs-MCPE. The exterior structures of unmodified carbon paste electrode (UCPE), MgO-MCPE and MgO-MWCNTs-MCPE were also studied by FESEM. The specific parameters including pH solution, varying speed rate and concentration of analytes were optimized at MgO-MWCNTs-MCPE. The electrode process was originated to be adsorption controlled movement and the detection limit (LOD) for GA, AD and EP was attained at 0.92, 1.49 and 0.83 μM respectively. The established electrode also contributed very good stability and reproducibility. The MgO-MWCNTs-MCPE portrays the very fine interface with these biological molecules and displayed the sufficient sensitivity and selectivity for individual and simultaneous study.

Electrochemical analysis of L-Tryptophan at highly sensitive poly(Glycine) modified carbon nanotube paste sensor

ABSTRACT In the present work, we developed poly(Glycine) modified carbon nanotube paste electrode (PGMCNTPE) as a biosensor for eliciting the electrooxidation of L-Tryptophan (TRP). The surface of the sensors was characterised by Field emission scanning electron microscopy (FE-SEM) and Electrochemical impedence spectroscopy (EIS). The analysis of TRP was succeeded at the surface of PGMCNTPE for their high electrical conductivity and electrostatic interaction, that amplified the oxidation peak current by 8 fold in cyclic voltammetry (CV) and by 12 fold in differential pulse voltammetry (DPV) as compared to unmodified electrode. The activity of sensor on TRP was manifested to be irreversible reaction proceeding with the transfer of 2e− and 2H+ and adsorption controlled. Under the optimal state, it was noteworthy that the execution of the sensor revealed to have a low detection limit of 0.42 μM on a broad linear range of 20 μM to 100 μM. Lastly, the determination of TRP was exploited successfully in the pharmaceutical supplement.

Rapid Electrochemical Monitoring of Tyrosine by Poly (Riboflavin) Modified Carbon Nanotube Paste Electrode as a Sensitive Sensor and its Applications in Pharmaceutical Samples

A poly(riboflavin) modified carbon nanotube paste electrode (PRFMCNTPE) is employed as a compatible and electrocatalytic sensor for the determination of Tyrosine (TYR). The analysis and assessment are carried out through differential pulse voltammetry (DPV) and Cyclic Voltammetry (CV). The surface of the intended sensor is examined through Field Emission Scanning Electron Microscopy (FE-SEM). The modified electrode shows the outstanding electrocatalytic effect for TYR with high selectivity and sensitivity as compared to carbon nanotube paste electrode (CNTPE). The electro-oxidation peak current of TYR and its concentration is found linear from 2 µM to 10 µM with a detection limit (LOD) of 0.45 µM. The developed sensor is productively applied for the determination of TYR in pharmaceutical samples like Tyrosine capsules. The adapted electrode shows good stability, excellent reproducibility, and remarkable sensitivity.

Polymerized carbon nanotube paste electrode as a sensing material for the detection of adrenaline with folic acid

A new intuition to construct the sensitive platform based on the poly(phenylmethanoic acid) modified carbon nanotube paste electrode (PPMAMCNTPE) to investigate the electroanalytical performance of adrenaline (AN), which acts as both neurotransmitter and hormone. The PPMAMCNTPE reveals a high detectability than the bare carbon nanotube paste electrode (BCNTPE) through cyclic voltammetry technique. The surface morphology and electrochemical conductivity of the BCNTPE and PPMAMCNTPE was characterized by field emission-scanning electron microscopy and electrochemical impedance spectroscopy. The number of factors affecting the analytical signal were optimized. The lowest detection limit (4.5 × 10–8 M) was gained within a linearity of the AN concentration range of 10–110 µM via differential pulse voltammetry approach at the PPMAMCNTPE. The designed sensor holds a great reproducibility, repeatability, and an outstanding anti-fouling feature. The PPMAMCNTPE possesses an admirable selectivity in the presence of folic acid. Finally, the PPMAMCNTPE was effectively implemented for the voltammetric detection of AN in both injection and blood serum samples.

Surfactant and Polymer Composite Modified Electrode for the Sensitive Determination of Vanillin in Food Sample

AbstractIn this work, the active poly (titan yellow) and octoxynol‐9 modified carbon nanotube paste electrode (PTOMCNPE) was prepared and characterized through a Field emission scanning electron microscope (FE‐SEM), Energy‐dispersive X‐ray spectroscopy (EDX), and Electrochemical impedance spectroscopy (EIS). PTOMCNPEpromotes the detection and quantification of vanillin (VA). The electrochemical parameters such as the number of electropolymerization cycles, effect of surfactant,pH, and scan rate were optimized to get an enhanced current signal for the targetmolecule. Under calibrated conditions, the concentration linearity for vanillin was obtained from 2.0‐40.0 μM using both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The limitof detection(LOD) for VA was found to be 4.9×10−8 M and 9.31×10−8 M using DPV and CV, respectively. The stable and selective VA sensor was applied to food analysis with excellent recovery.

Surfactant Assisted Electrochemical Determination of Noscapine and Papaverine by TiO2 Nanoparticles/Multi-Walled Carbon Nanotubes Modified Carbon Paste Electrode

Surfactant Assisted Electrochemical Determination of Noscapine and Papaverine by TiO2 Nanoparticles/Multi-Walled Carbon Nanotubes Modified Carbon Paste Electrode

Electrochemical sensing of adrenaline using surface modified carbon nanotube paste electrode

A new interesting insight into the construction of a voltammetric sensor for the detection of Adrenaline (AD) has been presented. Poly oxalic acid modified carbon nanotube paste electrode (POXMCNTPE) exhibited the boosted detecting ability towards the AD compared to the bare CNTPE (BCNTPE) as a sensing device. The detection of AD (pH 6.5) has been executed through the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) approaches. The surface morphological features, elemental analysis and electrochemical properties of the proposed electrode are revealed by Field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDS), Electrochemical impedance spectroscopy (EIS), and CV technique. The number of electropolymerisation cycles were optimized. The few factors influencing the voltammetric signal of AD, such as the impact of pH and the effect of scan rate were examined. The detection limit (DL) 3.1 × 10−8 M and quantification limit (QL) 1.0 × 10−7 M was gained from the proposed method. The designed sensor displayed the superb selectivity, good reproducibility, repeatability and an excellent antifouling property. Hence, the proposed procedure was effectively implemented to detect the AD in the injection sample and as well as in the blood serum sample. The accomplished outcome from the proposed electrode reveals that it is a favourable candidate for electrochemical sensing of AD.

Surface decoration of multi-walled carbon nanotubes modified carbon paste electrode with CuO nanoparticles for electrocatalytic oxidation of nitrite

In this paper, CuO nanoparticles were electrodeposited onto the film of multiwalled carbon nanotubes (MWCNTs) modified carbon paste electrode (MWCPE), which fabricated a sensitive nano-copper oxide coated multi-walled carbon nanotubes modified carbon paste electrode (CuO nano /MWCPE) to detect nitrite. Scanning electron microscope (SEM) image indicated that copper oxide nanoparticles desposited on MWCPE were homogeneous. The CuO nano /MWCPE was used to detect nitrite by square wave voltammetry (SWV) and cyclic voltammetry (CV) techniques. The sensor exhibited outstanding performance for the electrocatalysis of nitrite. Electrocatalytic oxidation of nitrite at the surface of CuO nano /MWCPE has been remarkably improved compared to the unmodified CPE and the MWCPE. Under optimum conditions the oxidation current was linear with the concentration of nitrite ion in the range of 5 μM – 1000 μM. The detection limit was evaluated to be 1.25 μM ( S/N = 3). The sensor was successfully used to determine nitrite in water samples with excellent recoveries.

Optimized Voltammetric Experiment for the Determination of Phloroglucinol at Surfactant Modified Carbon Nanotube Paste Electrode

Present work describes the electrochemical sensing and determination of phenolic compound (Phloroglucinol) using non-ionic surfactant Octyl phenol ethoxylate modified carbon nanotube paste electrode (OPEMCNTPE) in PBS (0.1 mol, pH 6.0) by Voltammetric method. The developed electrode was characterized by field emission scanning electron microscope (FE-SEM) and cyclic voltammetric (CV) studies. The OPEMCNTPE shows an exceptional catalytic impact towards the electro-oxidation of Phloroglucinol (PL) in contrast to the bare carbon nanotube paste electrode (BCNTPE). The rise in the concentration of PL is directly proportional to PL anodic peak current in the linear working range 10–90 µmol with a small detection limit (LOD) 0.71 µmol. This method was utilized for the estimation of PL in the water and blood serum samples.

Zinc Oxide Nanoparticles Supported on Multi‐walled Carbon Nanotube Modified Electrode for Electrochemical Sensing of a Fluoroquinolone Drug

AbstractA facile, and novel construction strategy invented on electrochemical procedures for the assemblage of zinc oxide nanoparticles (ZnO NPs) with a multiwalled carbon nanotube modified carbon paste electrode (ZnO‐MWCNTMCPE) to ascertain the fluoroquinolone drug‐Moxifloxacin (MOX). The ZnO‐MWCNTMCPE can significantly improve the electron transfer process and lessen the impedance of the surface of the electrode. Besides, the oxidation of MOX has remarkably enhanced on the modified electrode. Under the optimal experimental conditions, the empirical results exhibited that the oxidation peak current was linearly proportional to the concentration of MOX in the range of 1.0×10−7 to 2.4×10−6 mol L−1 with a detection limit of 0.452×10−7 mol L−1. To analyze the practicality of the MOX determination technique in real samples, the intended sensor manipulated for the adjudication of MOX in human urine specimens, and the results authenticated the explore of MOX with the highest accuracy. Further, the proposed sensor system exercised for the simultaneous evaluation of paracetamol (ACOP) and MOX, the DPV technique unveiled the well‐separated peaks among ACOP (0.188 mV) and MOX (0.814 mV) with a peak separation (ΔE) of 626 mV in real samples. Therefore, the suggested system could sense and discover the MOX in the biological systems.

Amplified oxadiazole derivative nano MgO–multiwall carbon nanotubes modified carbon paste electrode for the determination of dopamine in presence of morphine

AbstractIn this paper, we report the fabrication of an amplified sensor to determine dopamine in the presence of morphine based on nano‐MgO, multiwall carbon nanotubes, and an oxadiazole derivative. The electrochemical behavior and electrocatalyic activity of the sensor toward the oxidation of dopamine were investigated. Cyclic voltammetry was used to study the redox features of the sensor, and the results have shown that dopamine overpotential oxidation at the surface of the sensor was reduced to nearly 460 mV. The diffusion coefficient was estimated by chronoamperometry. Three segmented linear dynamic ranges over the range 0.05–5175.0 and detection limit of 0.021 μM for the quantification of dopamine were obtained using differential pulse voltammetry (DPV). The modified nanocomposite carbon paste electrode, which showed excellent sensitivity, selectivity, repeatability, and reproducibility, was satisfactorily employed to determine dopamine and morphine in actual samples.

Enhanced voltammetric detection of paracetamol by using carbon nanotube modified electrode as an electrochemical sensor

New aspects associated with electro-catalytic activity of poly(methyl orange) modified carbon nanotube paste electrode (PMMCNTPE) towards the detection of paracetamol (PC) which is typically used worldwide as a pain reliever, were explored through implementation of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Bare carbon nanotube paste electrode (BCNTPE) was modified by methyl orange using the electro­polymerizing method. The effect of pH and influence of potential scan rate were resolved by means of CV technique. It was found that under optimized experimental conditions, PMMCNTPE imparts the analytical curve for PC in the concentration range of 2.0×10-6 – 5.0×10-5 M with detection limit of 3.8×10-8 M and limit of quantification of 1.2×10-8 M. The proposed sensor exhibited acceptable reproducibility, admirable stability, and adequate repeatability. The interference study of PC with dopamine (DA) and folic acid (FA) showed good selectivity of the designed sensor. The feasibility of the constructed electrochemical sensor to detect PC was successfully tested in some pharmaceutical formulations.