Nanocomposite Carbon Paste Electrode Research Articles

A Novel Electrochemical Sensor Based on an Environmentally Friendly Synthesis of Magnetic Chitosan Nanocomposite Carbon Paste Electrode for the Determination of Diclofenac to Control Inflammation.

A simple and eco-friendly electrochemical sensor for the anti-inflammatory diclofenac (DIC) was developed in a chitosan nanocomposite carbon paste electrode (M-Chs NC/CPE). The M-Chs NC/CPE was characterized with FTIR, XRD, SEM, and TEM for the size, surface area, and morphology. The produced electrode showed a high electrocatalytic activity to use the DIC in 0.1 M of the BR buffer (pH 3.0). The effect of scanning speed and pH on the DIC oxidation peak suggests that the DIC electrode process has a typical diffusion characteristic with two electrons and two protons. Furthermore, the peak current linearly proportional to the DIC concentration ranged from 0.025 M to 4.0 M with the correlation coefficient (r2). The sensitivity, limit of detection (LOD; 3σ), and the limit of quantification (LOQ; 10σ) were 0.993, 9.6 µA/µM cm2, 0.007 µM, and 0.024 µM, respectively. In the end, the proposed sensor enables the reliable and sensitive detection of DIC in biological and pharmaceutical samples.

Recent development of eco-friendly nanocomposite carbon paste electrode for voltammetric determination of Cd(II) in real samples

Using eco-friendly, cheap, and available adsorbents is promising for the determination of metal ions. So, this study focuses on the modification of graphite reinforcement carbon paste electrode (GRCPE) with mango seed kernel (MSK) for voltammetric determination of Cd(II). Moreover, to increase the surface area of this adsorbent, it was prepared in nanosized that formed nanoparticles of mango seed kernel (MSK-NPs). The developed nanocomposite electrode of carbon paste electrode modified with nanoparticles of mango seed kernel (MSK-NPs@GRCPE) was characterized using Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM). The effect of pH, buffer solution, and supporting electrolyte as experimental conditions were optimized through differential pulse adsorptive anodic stripping voltammetric method (DPAdASV). Britton-Robinson buffer pH = 3.9 at Eacc = – 1400 mV, tacc = 30 s, pulse width = 10 ms and sampling time = 8 ms were the optimum conditions for determination of Cd(II). The LOD and LOQ of MSK-NPs@GRCPE were calculated at 5.44 × 10–9 and 1.65 × 10–8 M, respectively. Compared with bare graphite reinforcement carbon paste electrode (BGRCPE), the nanocomposite MSK-NPs@GRCPE has a lower detection limit, indicating that the presence of MSK-NPs could greatly improve the response to Cd(II). The practical applicability of the electrode was verified by the determination of Cd(II) in chocolate and white rice samples. The results show high selectivity and sensitivity for Cd(II) in real samples.Graphical abstract

0D polymer nanocomposite carbon-paste electrodes using carbon nanohorns: Percolating networks, electrochemical achievements and filler comparison

In this preliminary work, carbon nanohorns (CNHs) have been dispersed for the first time in an inert polymeric matrix for the development of a new 0D CNH-based polymer nanocomposite carbon-paste electrode (pNC–CPE). As a first demonstration, the electrically conductive networks were optimized by tuning the filler/polymer composition ratio in order to achieve transducers with enhanced electroanalytical responses. Further, direct electrochemical comparison with additional pNC–CPEs employing conventional carbon nanoallotropes is provided, demonstrating that pNC–CPEs can be electrically modulated by customizing the filler/polymer composition ratio as well as the carbon nature. Consequently, this work wide the pNC–CPE family and paves the way for exploiting CNH-based polymer nanocomposites as novel sensitive and reproducible electrochemical (bio)sensing devices.

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.

Cyclodextrin-based superparamagnetic host vesicles as ultrasensitive nanobiocarriers for electrosensing.

A carbohydrate-based nanohybrid of superparamagnetic nanoparticles embedded in unilamellar bilayer vesicles of amphiphilic β-cyclodextrins (magnetic cyclodextrin vesicles, mCDVs) has been engineered as a novel magnetic biorecognition probe for electrosensing. As a proof-of-concept, the synergistic properties of these mCDVs on a magneto nanocomposite carbon-paste electrode (mNC-CPE) have been used for the picomolar determination of thyroxine (T4) as a model analyte (taking advantage of the host-guest chemistry of β-cyclodextrin and T4), resulting in the most sensitive electrochemical T4 system reported in the literature. Accordingly, a first demonstration of mCDVs as alternative water-soluble magnetic nanobiocarriers has been devised foreseeing their successful use as alternative electrochemical biosensing platforms for the supramolecular trace determination of alternative targets.

Carbon nanotube-based nanocomposite sensor tuned with a catechol as novel electrochemical recognition platform of uranyl ion in aqueous samples

This article reports a novel electrochemical recognition platform based on a nanocomposite carbon paste electrode containing carbon nanotubes modified with gold nanoparticles carrying a thiolated catechol for the fast amperometric determination of uranyl ion (UO22+) in water. Recognition of UO22+ is accomplished by supramolecular chemistry due to the formation of an inclusion complex between catechol and UO22+. The amperometric device operates at –0.40 V vs. Ag/AgCl, where the reduction of UO22+ takes place on the electrode surface, covering a linear range from 0.49 to 170 μg L−1 UO22+ in a 0.1 M boric acid buffer solution at pH 5.3. The developed sensing system presents good response towards UO22+ in aqueous environmental samples, with good selectivity over other browsed cations and can be easily reset by simple polishing. This platform has demonstrated to be a potential alternative regarding to the common standard bench-top analytical techniques for the development of in-field devices for in-situ monitoring.

A novel samarium(III) nanocomposite carbon paste electrode based on N,N'- bis(8-quinolyl)pyridine-2,6-dicarboxamide as a selectophore

A novel samarium(III) nanocomposite carbon paste electrode based on N,N'- bis(8-quinolyl)pyridine-2,6-dicarboxamide as a selectophore

Highly Selective Voltammetric Sensor Based on Molecularly Imprinted Polymer and Carbon Nanotubes to Determine the Dicloran Pesticide in Biological and Environmental Samples

Despite of increasing the food production by application of pesticides, the wide use of them can lead to environmental pollution and their residues in food. Due to the increasing application of pesticides, reliable and accurate analytical methods are necessary to analyze different occupational and environmental samples like air, water, soil, as well as also food containing these compounds. There are some traditional techniques to determine the pesticides such as liquid chromatography and gas chromatography with electron capture detection. The mentioned techniques are very expensive and a well-equipped laboratory and well-trained analysis operators are required. A sample pre-treatment step is needed to determine the analytes at ppb levels. Therefore, in the last few years many sensitive, selective, and accurate methods have been developed to determine the trace toxic species like pesticides. Electrochemical sensors are the appropriate and interested devices to monitor the trace and even ultra-trace pesticides. Molecular imprinted polymers (MIPs) can be used as recognition elements or modifying agents in sensors structure to increase their selectivity and improve their response. Recently, modified electrode by different modifying agents like MIPs and various nano structures are being used for quantification of analytes because of their interesting advantages. Modified electrodes may be used in combination with different electrochemical techniques. The aim of this study was to synthesize a molecularly imprinted polymer for dicloran for first time and then to apply it as a recognition element in the nano-composite carbon paste electrode for selective and sensitive electrochemical determining the dicloran pesticide in environmental and biological samples. Multi-walls carbon nanotubes (MWCNTs) and a molecularly imprinted polymer (MIP) were used as the modifiers in senor composition. A dicloran selective MIP and a non-imprinted polymer (NIP) were synthesized and applied in the carbon paste electrode. To prepare the bare carbon paste electrode (CP), graphite, MWCNT and paraffin oil were mixed. The MIP-CP and NIP-CP were prepared by mixing different percentages of graphite, MWCNT, paraffin oil, and MIP or NIP. This mixture was homogenized and final paste was packed into the end of an electrode body. After the optimization of electrode composition, it was used to extract the analyte in the sample and then was inserted in the electrochemical cell to determine the concentration of extracted analyte. Some parameters affecting the sensor response were optimized in the extraction and analysis steps, such as sample pH, electrolyte concentration and pH, stirring rate of analyte solution, as well as the instrumental parameters of square wave voltammetry (square wave amplitude and frequency, deposition potential and its exertion time, and electrolyte concentration). The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. The CP containing 22% MIP and 3% MWCNTs had the highest efficiency to adsorb the analyte and it was selected for later experiments. The electrode with MIP was very selective for dicloran, so that, other pesticides indicated no significant impact on its responses. Findings demonstrated the ability of MIP-CP electrode to interact strongly with the target compound due to specific cavities for molecules of interest in the MIP structure. The optimum conditions to extract the analyte on the electrode surface included the extraction pH of 6, the solution stirring rate of 700 rpm, and the extraction time of 20 min. In addition, the optimum analysis conditions were obtained as follow: the square wave amplitude 0.15 V, frequency 150 Hz, deposition potential of -0.5 V, its exertion time of 15s, analysis pH of 8, and electrolyte (KCl) concentration of 0.04 mol L-1. After optimization of all effective parameters on electrochemical determination of dicloran, the difference between responses of prepared MIP and NIP was studied. There was significant difference (P< 0.05) between these polymers to adsorb dicloran molecules, proving the formation of selective adsorption sites in the MIP structure. Figure 1 indicates the square wave voltammograms related to determination of defined concentration of dicloran by MIP-CP, NIP-CP, and bare CP. Finally in method validation, the obtained linear range in calibration curve was 1×10-6 to 1×10-9 molL-1 (R2: 0.987), The limit of detection (LOD) and limit of quantification (LOQ) were 4.8×10-10 and 9.4×10-10 mol L-1, respectively. In this work, a high selective square wave voltammetric sensor for the rapid detection of trace amounts of dicloran in environmental and biological samples has been designed and applied. The modification of electrode can considerably enhance the selective response of electrode to determine the analyte of interest. The designed sensor was successfully used for determination of dicloran in different real samples (tap water, river water, and urine) with no special sample preparation procedure. The ability of MIP-CP electrode to interact strongly with the target compound due to specific cavities lead to high selectivity.

New tools for pesticide risk assessment through biological monitoring and exposure modelling in diverse agricultural exposure scenarios

Despite of increasing the food production by application of pesticides, the wide use of them can lead to environmental pollution and their residues in food. Due to the increasing application of pesticides, reliable and accurate analytical methods are necessary to analyze different occupational and environmental samples like air, water, soil, as well as also food containing these compounds. There are some traditional techniques to determine the pesticides such as liquid chromatography and gas chromatography with electron capture detection. The mentioned techniques are very expensive and a well-equipped laboratory and well-trained analysis operators are required. A sample pre-treatment step is needed to determine the analytes at ppb levels. Therefore, in the last few years many sensitive, selective, and accurate methods have been developed to determine the trace toxic species like pesticides. Electrochemical sensors are the appropriate and interested devices to monitor the trace and even ultra-trace pesticides. Molecular imprinted polymers (MIPs) can be used as recognition elements or modifying agents in sensors structure to increase their selectivity and improve their response. Recently, modified electrode by different modifying agents like MIPs and various nano structures are being used for quantification of analytes because of their interesting advantages. Modified electrodes may be used in combination with different electrochemical techniques. The aim of this study was to synthesize a molecularly imprinted polymer for dicloran for first time and then to apply it as a recognition element in the nano-composite carbon paste electrode for selective and sensitive electrochemical determining the dicloran pesticide in environmental and biological samples.Multi-walls carbon nanotubes (MWCNTs) and a molecularly imprinted polymer (MIP) were used as the modifiers in senor composition. A dicloran selective MIP and a non-imprinted polymer (NIP) were synthesized and applied in the carbon paste electrode. To prepare the bare carbon paste electrode (CP), graphite, MWCNT and paraffin oil were mixed. The MIP-CP and NIP-CP were prepared by mixing different percentages of graphite, MWCNT, paraffin oil, and MIP or NIP. This mixture was homogenized and final paste was packed into the end of an electrode body. After the optimization of electrode composition, it was used to extract the analyte in the sample and then was inserted in the electrochemical cell to determine the concentration of extracted analyte. Some parameters affecting the sensor response were optimized in the extraction and analysis steps, such as sample pH, electrolyte concentration and pH, stirring rate of analyte solution, as well as the instrumental parameters of square wave voltammetry (square wave amplitude and frequency, deposition potential and its exertion time, and electrolyte concentration).The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. The CP containing 22% MIP and 3% MWCNTs had the highest efficiency to adsorb the analyte and it was selected for later experiments. The electrode with MIP was very selective for dicloran, so that, other pesticides indicated no significant impact on its responses. Findings demonstrated the ability of MIP-CP electrode to interact strongly with the target compound due to specific cavities for molecules of interest in the MIP structure. The optimum conditions to extract the analyte on the electrode surface included the extraction pH of 6, the solution stirring rate of 700 rpm, and the extraction time of 20 min. In addition, the optimum analysis conditions were obtained as follow: the square wave amplitude 0.15 V, frequency 150 Hz, deposition potential of -0.5 V, its exertion time of 15s, analysis pH of 8, and electrolyte (KCl) concentration of 0.04 mol L-1. After optimization of all effective parameters on electrochemical determination of dicloran, the difference between responses of prepared MIP and NIP was studied. There was significant difference (P< 0.05) between these polymers to adsorb dicloran molecules, proving the formation of selective adsorption sites in the MIP structure. Figure 1 indicates the square wave voltammograms related to determination of defined concentration of dicloran by MIP-CP, NIP-CP, and bare CP. Finally in method validation, the obtained linear range in calibration curve was 1×10-6 to 1×10-9 molL-1 (R2: 0.987), The limit of detection (LOD) and limit of quantification (LOQ) were 4.8×10-10 and 9.4×10-10 mol L-1, respectively.In this work, a high selective square wave voltammetric sensor for the rapid detection of trace amounts of dicloran in environmental and biological samples has been designed and applied. The modification of electrode can considerably enhance the selective response of electrode to determine the analyte of interest. The designed sensor was successfully used for determination of dicloran in different real samples (tap water, river water, and urine) with no special sample preparation procedure. The ability of MIP-CP electrode to interact strongly with the target compound due to specific cavities lead to high selectivity.

Fabrication of a new Pr3+ nanocomposite carbon paste electrode based on bis(salicylaldehyde)thiocarbohydrazone as a material sensing

Fabrication of a new Pr3+ nanocomposite carbon paste electrode based on bis(salicylaldehyde)thiocarbohydrazone as a material sensing

Determination of copper ions in foodstuff products with a newly modified potentiometric carbon paste electrode based on a novel nano-sensing layer

In the present study, a novel nano-layer sensing materials for the fabrication of a newly modified potentiometric carbon paste electrode was introduced. Its sensing layer was prepared with the incorporation of 1-(3-imino-4-hydroxophenylazo-4 nitrobenzene) isonicotinohydrazide “as an efficient ionophore” into the matrix consisting of graphite powder, synthesized graphene nanosheets, synthesized CdO nanowires, and diphenylacetylene (a typical molecular wire as the conductive binder). The suggested nanocomposite carbon paste electrode gave a Nernstian behavior in the linear range of 3.50 × 10−9 to 1.00 × 10−2 M with the detection limit of 1.44 × 10−9 M. For investigation of the electrochemical behavior of Cu2+ at the surface of the unmodified and modified electrodes, the differential pulse voltametric method was used. The proposed sensor was successfully applied in the determination of copper ions in some foodstuff real samples with satisfactory results.

Electrocatalytically active nanocomposite carbon paste electrode modified with SiO2/poly (P-phenylendiamine) core/shell nanoparticles: application toward electro-oxidation of hydrazine

This research highlights fabrication, characterization, and performance of a carbon paste electrode modified by a nanocomposite having poly(P-phenylendiamine) (PpDP) and silica nanoparticles as novel potential electrocatalyst for hydrazine oxidation. The core/shell structure morphology and size of PpDP and its nanocomposite were investigated by scanning electron microscopy and transmission electron microscopy techniques. Catalytic activity and stability of the fabricated carbon paste electrode (CPE) was evaluated using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The results confirmed that the nanocomposite significantly enhances the catalytic activity of the CPE. The kinetic parameters of the electron transfer coefficient and diffusion coefficient of hydrazine were also determined and compared. It was also evidenced that the core/shell morphology of the nanocomposite improves effective dispersion of silica nanoparticles facilitating the easier access of hydrazine to the catalytic sites.

Determination of methyl parathion in liquid phase by nano-composite carbon paste surface biosensor and differential FFT continuous linear sweep voltammetry

A methyl parathion (MP) DNA biosensor was constructed using Au nanoparticles doped in polymeric film on nano-composite carbon paste electrode. The nano-composite carbon paste (NCCPE) was composed of ionic liquid (IL), graphene nanosheets, Pt nanoparticles and graphite. The carbon paste electrode surface was covered by polypyrrole (PPy) film. It was seen that the existence of Pt NPs causes a better electrochemically deposition of PPy on NCCPE surface. The film was then doped with Au nanoparticles, and then, it was modified by a dd-DNA. The characterization of the biosensor surface was studied by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) methods. The biosensor response was obtained by differential fast Fourier transformation continuous linear sweep voltammetry (DFFTCLSV) technique, in which the change of the charge under curve (in form of coulomb) in a specific potential range was calculated. The combination of nanoparticles and conducting polymeric layer catalyzed the electron transfer, which amplifies the biosensor sensitivity. The result shows that the biosensor response was proportional to analyte concentration in the range of 10 to 300nM, with a detection limit of 1.3nM. Experimental parameters which affect the sensitivity of the biosensors were studied. The biosensor showed good reproducibility, long-term storage stability and accuracy.

Square wave voltammetric determination of captopril in liquid phase using N-(4-hydroxyphenyl)-3,5-dinitrobenzamide modified ZnO/CNT carbon paste electrode as a novel electrochemical sensor

The electrocatalytic oxidation of captopril (CAP) has been studied by N-(4-hydroxyphenyl)-3,5-dinitrobenzamide (N-HPDB) modified ZnO/CNT nanocomposite carbon paste electrode (N-HPDB/ZnO/CNTs/CPE). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry were used to investigate the suitability of N-HPDB as a mediator for the electrocatalytic oxidation of CAP in aqueous solution. The catalytic reaction rate constant, kh was calculated (2.28×103M−1s−1) using chronoamperometry. The square wave voltammetric (SWV) peak currents of the electrode increased linearly with the corresponding CAP concentration in the range of 5.0×10−8M–8.0×10−4M with a detection limit of 1.0×10−8M.