Nanoparticles Modified Carbon Paste Electrode Research Articles

Response Surface Modeling of Electrochemical Data for Sensitive Determination of Sudan III in Food Products at the Surface of a Nanocomposite Modified Electrode

In this work, application of a sensitive electrochemical technique assisted with multivariate optimization methods is presented for detection of Sudan III in food samples. At first, the synthesis and characterization of zinc oxide nanoparticles (ZnONPs) are described. The precipitation method is used for synthesis of ZnONPs with average particle sizes ranging from 20 to 30 nm. The structural analysis of the samples is performed using XRD. Also, the morphology and particle sizes of the ZnONPs are confirmed by SEM. Next, the nanoparticles are used for modification of a carbon paste electrode (CPE) surface. The modified electrode is used for investigation of electrochemical behavior of Sudan III. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques are applied for characterization of the nanostructure modified electrode. For achieving the best response for Sudan III, effective experimental factors on the voltammetric determination of the analyte are optimized by rotatable central composite design (RCCD) and response surface methodology (RSM). The nanostructured modified electrode shows an excellent electrocatalytic property on the oxidation peak current of Sudan III. The electrochemical behavior of Sudan III at the surface of zinc oxide nanoparticles modified carbon paste electrode (ZnONPs/CPE) are investigated by differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronocoulometry. Analytical parameters such as linearity, selectivity, repeatability, and stability are also investigated. At the optimized conditions, the linear dynamic ranges for Sudan III are obtained 0.05–1.0 and 1.0–15.0 μM and the detection limit is achieved 2.56 nM. Also, the proposed sensor is successfully applied for detection of Sudan III in real complicated samples.

Sensitive Electrochemical Determination of Hyperin Based on Electrochemically Activated ZrO2 Nanoparticles-Modified Carbon Paste Electrode

A novel electrochemically activated ZrO2 nanoparticles modified carbon paste electrode (CPE) (ZrO2-CPE(ox)) was prepared and applied for selective and sensitive determination of hyperin. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and electrochemical experiment were used to characterize the ZrO2 nanoparticles and investigate the electrochemical performance of the ZrO2-CPE(ox). Compared with bare CPE and electrochemically activated CPE (CPE(ox)), the ZrO2-CPE(ox) got more reactive sites by electrochemical treatment and exhibited larger effective surface area and more excellent electrochemical catalytic activity toward the redox of hyperin. Under the optimum conditions, the oxidation peak currents showed a linear relationship with the concentrations of hyperin in the range of [Formula: see text]–[Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text] and [Formula: see text]–[Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text], and a low detection limit of [Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text] was achieved for hyperin. Moreover, the proposed method exhibited an excellent selectivity, stability, reproducibility and repeatability, which make it very suitable for a potential choice for determining the concentrations of hyperin in drug matrices.

Nanomolar Detection of Dopamine at ZnO/Graphene Modified Carbon Paste Electrode

In the present work, we demonstrate the electrocatalytic activity of few layer graphene and wurzite ZnO nanoparticles modified carbon paste electrode towards the oxidation of dopamine. Cost effective, simple and fast solution combustion synthesis was utilized for the synthesis of pure crystalline phase of wurzite ZnO nanoparticles. The commercial few layer graphene and ZnO modifiers were uniformly incorporated into the carbon paste matrix by simple bulk modification technique. The modified electrode enhanced the current sensitivity and resolved the DA peak from interfering molecules such as ascorbic acid and uric acid. The electrode has a detection limit of 60 nM having a wide linear dynamic range of 80 μM–80 nM. The fabricated sensor has excellent stability and reproducibility. The sensor was successfully utilized for the quantification of dopamine in blood serum.

Enantioselective biomimetic sensor for discrimination of R and S-Clopidogrel promoted by β-cyclodextrin complexes employing graphene and platinum nanoparticle modified carbon paste electrode

To mimic the enantioselectivity of an enzyme in the field of biosensor for a drug molecule is daunting task for chiral selector. Here, we report beta cyclodextrin (β-CD) as artificial enzyme model for molecular recognition of Clopidogrel (CLP) isomers on chiral carbon paste electrode. The inclusion of CLP enantiomers was initiated by β-CD and stability constants obtained for 1:1 complex of β-CD-R-CLP and β-CD-S-CLP. The stability constants calculated for β-CD-R-CLP and β-CD-S-CLP were 6.109×103M−1 and 5.023×102M−1, respectively at 25°C. The best enantioselectivity was obtained for R-CLP which was found to be 12 times higher to that of S-CLP. The thermodynamic consideration of the complex formation shows negative values of Gibbs free energy (ΔG) -21.602 kJ K−1mol−1 (R-CLP) and−15.411 kJ K−1mol−1 (S-CLP) which indicates inclusion process to be exothermic and spontaneous. The difference in ΔG values indicates effective enantiomeric recognition of the aforementioned electrode systems for CLP. The synergistic effect of graphene, platinum nanoparticle and beta cyclodextrin in the form of modified carbon paste electrode (GNS-PNP-β-CD-CPE) were studied by differential pulse voltammetric techniques. The anodic peak potential difference of 102mV was able to discriminate isomers of CLP at the surface of GNS-PNP-β-CD-CPE. Under optimum conditions, R-CLP and S-CLP exhibited good linear response in the range of 2.0×10−6 to 2.0×10−4M with low detection limit of 4.87×10−7M and 2.10×10−7M, respectively. The Michaelis-Menten constants (KM) calculated for R-CLP and S-CLP were 44.0μM and 60.0μM employing chronoamperometry. The higher value of KM for S-CLP suggests weak binding of S-CLP to the β-CD confirming catalytically different biotransformation rate of each enantiomer towards oxidation. Although the kinetic parameters do not match the level of enzymatic transformations, this study predicts the Michaelis-Menten constants for CLP using β-CD which may become useful guide for future exploration of enzyme mimics in the area of chiral electrochemical biosensor.

Electrochemical preconcentration of ultra-trace Cd2+ from environmental and biological samples prior to its determination using carbon paste electrode impregnated with ion imprinted polymer nanoparticles

ABSTRACTCadmium (Cd) is known as one of the most toxic elements among the heavy metals. This study proposes an electrochemical preconcentration method using the ion imprinted polymer nanoparticles modified carbon paste electrode (IIP-CPE) for the stripping voltammetry determination of Cd2+ in the environmental and biological samples. These IIP NPs were synthesised using ethylene glycol dimethacrylate as the cross-linker, 2,2ʹ-azobisisobutyronitrile as the free radical initiator and 4ʹ-(4-vinylphenyl)-2,2ʹ:6ʹ,2ʺ-terpyridine as the Cd-binding ligand. The calibration plot was linear in the concentration range of 4–500 nM (R2 = 0.9936) with a sensitivity of 918 µA µM−1 cm−2. The LOD based on 3Sb/m (where m is the slope of the calibration curve and Sb is the standard deviation for five blank measurements) was found to be 1.94 nM. The relative standard deviations (RSDs) for single-electrode repeatability and electrode-to-electrode reproducibility were 3.0% and 5.6% (n = 5), respectively. The accuracy of the current method was confirmed by the analysis of urine quality control material (QCM, SeronormTM Trace Elements Urine, REF NO 201205, Norway) and spiked blood, rice and water samples. Recoveries were found to be above 95.0% for all samples, which confirms the good performance of the proposed voltammetry method.

Voltammetric Study of Ascorbic Acid Using Polymelamine/Gold Nanoparticle Modified Carbon Paste Electrode

Polymelamine/gold nanoparticle modified carbon paste electrode (PM/AuNPs/CPE) has been developed for voltammetric study of ascorbic acid (AA). The PM/CPE was prepared onto carbon paste electrode surface via electropolymerization, then it has been deposited gold nanoparticle (AuNPs) via electrodeposition for PM/AuNPs/CPE. In pH 7.0 phosphate buffer, PM/AuNPs/CPE was oxidized during the cyclic potential sweep between 0.0 V and 1.5 V, forming polymer and gold nanoparticle at the carbon paste electrode (CPE) surface. The electrochemical behavior of ascorbic acid at the bare CPE, PM/CPE, AuNPs/CPE and PM/AuNPs/CPE were investigated. The oxidation peak potential of ascorbic acid shifts to more negative potential at PM/AuNPs/CPE Moreover, the oxidation peak current significantly increases at PM/AuNPs/CPE. The PM/AuNPs/CPE electrode exhibits a quasi-reversible electron with a peak separation 130 mV. These fenomena indicate that PM/AuNPs/CPE shows highly-efficient catalytic activity to the oxidation of ascorbic acid.

Voltammetric sensor for secretolytic agent ambroxol at titanium dioxide nanoparticles modified electrode

Voltammetric sensor has been developed for secretolytic agent, ambroxol at titanium dioxide nanoparticles modified carbon paste electrode (CPE). It was observed that, modified electrode was enhanced the peak current remarkably in phosphate buffer solution (PBS) as compared to other buffer solutions like Britton and Robinson buffer solutions and citrate buffer solutions. Effect of other electrochemical parameters like pH, accumulation time, scan rate, concentration, were studied at various voltammetric techniques. The use of TiO2 nanoparticles shows an increment in the peak current with shifts in the potential to less negative values. Based on the experimental data obtained, number of electrons /protons transferred and rate constant were calculated. The developed sensor was applied for the determination of ambroxol in pharmaceutical and urine samples.

Synthesis of a simply modified electrochemical nicotine sensor based on silver nanoparticles

An innovative electrochemical nicotine modified sensor was created by chemically mixing a carbon paste with silver nano powder to prepare an Ag nanoparticle modified carbon paste electrode. Different electrochemical techniques including cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy in both aqueous and micellar media were used. The surface morphology was also detected using scanning electron microscope and energy dispersive X-ray analysis techniques. Nicotine measurements were investigated in Britton–Robinson buffer solutions with a pH range of 2.0–8.0 containing 1.0 mmol/L sodium dodecyl sulfate. The electrode-based NIC sensor exhibited a high sensitivity in quantitative analysis, and its detection limit could be as low as 0.0036 μmol/L with linearity ranging from 0.8 μmol/L to 800 μmol/L. In addition, due to its good reproducibility, anti-interference performance, and long-term stability, the proposed sensor is capable of detecting trace levels of nicotine in urine samples and different brands of commercial cigarettes.

Fabrication of copper oxide nanoparticles modified carbon paste electrode and its application in simultaneous electroanalysis of guanine, adenine and thymine

Copper oxide nanoparticles (CuO NPs) were synthesized by the effortless co-precipitation method. The morphology, structure and optical characterization were investigated by scanning electron microscopy (SEM), X-ray diffraction, Fourier transform-infrared, (FTIR) and Ultra-Violet (UV) spectroscopy. The results specified that the resultant CuO NPs possess an average diameter of 12 nm and were effectively deposited on carbon paste electrode. The analytical performance of this novel CuO NPs modified carbon paste electrode (CuO NPsMCPE) was demonstrated the interference-free determination of guanine (G), adenine (A), and thymine (T) concurrently in a ternary mixture with phosphate buffer (PB) solution. The electrochemical investigation was carried out using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance (EIS) spectroscopy demonstrated the potent and persistent electro-oxidation performance followed by well-separated oxidation peaks towards the detection of G, A and T. Besides this, the sensor manifested a wide linear range of 1–80 μM, 1–80 μM and 1–210 μM with the detection limit of 0.687, 0.472, and 0.111 μM for G, A and T correspondingly. The advantages of the deliberated sensor encompass good electrocatalytic activity, fast electron transfer rate, high accessible surface area and antifouling features towards the estimation and low investment of fabrication.

NiO nanoparticles modified carbon paste electrode as a novel sulfasalazine sensor

The sol-gel synthesized NiO nanoparticles were characterized and used for the modification of a carbon paste electrode (CPE) in electrocatalytic voltammetric determination of sulfasalazine. Calcination temperature of NiO had an important role on the peak current of the modified NiO-CPE and calcined NiO at 200 °C had the best and maximum peak current for the corresponding electrode. Jahn-Teller and a Z-out effects for the singlet electrons in their 3dz2 orbital for calcined NiO at 200 °C relatively instable such electrons and hence they can easily participate in the electro-oxidation process. The electrochemical impedance spectroscopy (EIS) results confirmed that the modified CPE by calcined NiO at 200 °C has lower charge transfer resistance. In interaction effects study between the experimental variables by using the response surface methodology (RSM) approach, the optimized run included the 17.5% of NiO modifier, 0.5 M NaOH, amplitude of 295 mV, step potential of 7 mV and frequency of 15 Hz. A calibration plot in the range of 0.009–1.6 μM with limits of detection (LOD) and quantification (LOQ) of 0.002 and 0.006 μM was obtained, respectively. The modified electrode showed good selectivity and applicability for SSZ determination in complex matrixes.

A simple ultrasensitive electrochemical sensor for simultaneous determination of gallic acid and uric acid in human urine and fruit juices based on zirconia-choline chloride-gold nanoparticles-modified carbon paste electrode

The determination of gallic acid (GA) and uric acid (UA) is essential due to their biological properties. Numerous methods have been reported for the analysis of GA and UA in various real samples. However, the development of a simple, rapid and practical sensor still remains a great challenge. Here, a carbon paste electrode (CPE) was modified by nanocomposite containing zirconia nanoparticles (ZrO2NPs), Choline chloride (ChCl) and gold nanoparticles (AuNPs) to construct ZrO2-ChCl-AuNPs/CPE as electrochemical sensor for the simultaneous electro-oxidation of GA and UA. Characterization was performed by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The modified electrode was investigated by different methods including electrochemical impedance spectroscopy and cyclic voltammetry. Kinetic parameters such as charge transfer coefficient, standard heterogeneous electron transfer rate constant and other parameters were calculated via voltammetry techniques. Differential pulse voltammetry was used for simultaneous determination of GA and UA applying the ZrO2-ChCl-AuNPs/CPE electrode. At the optimum conditions, this sensor showed a linear response in the ranges 0.22– 55 and 0.12–55 µM for GA and UA, respectively. In addition, low detection limits of 25 and 15 nM were obtained for GA and UA, respectively. Furthermore, ZrO2-ChCl-AuNPs/CPE was successfully applied for the independent determination of GA in green tea and fruit juice as well as the simultaneous determination of GA and UA in human urine samples.

Voltammetric sensor for electrochemical determination of the floral origin of honey based on a zinc oxide nanoparticle modified carbon paste electrode

Abstract. A new methodology based on cyclic voltammetry using a chemically modified electrode has been developed for the discrimination of the floral origin of honey. This method involves an electronic tongue with an electrochemical sensor made from a carbon paste (CPs) electrode where zinc oxide (ZnO) nanoparticles are used as an electroactive binder material. The bare CPs electrode is evaluated for comparison. The electrochemical response of the modified electrode in 50 samples of five different floral types of honey has been analysed by the cyclic voltammetric technique. The voltammograms of each floral variety of honey reflect the redox properties of the ZnO nanoparticles present inside the carbon paste matrix and are strongly influenced by the nectar source of honey. Thus, each type of honey provides a characteristic signal which is evaluated by using principal component analysis (PCA) and an artificial neural network (ANN). The result of a PCA score plot of the transient responses obtained from the modified carbon paste electrode clearly shows discrimination among the different floral types of honey. The ANN model for floral classification of honey shows more than 90 % accuracy. These results indicate that the ZnO nanoparticles modified carbon paste (ZnO Nps modified CPs) electrode can be a useful electrode for discrimination of honey samples from different floral origins.

Electrochemical sensor for the determination of ketoconazole based on gold nanoparticles modified carbon paste electrode

The present research work is devoted to a carbon paste electrode modified with gold nanoparticles for the detection of low concentration of ketoconazole (KCZ). A simple preparation procedure for gold nanoparticles (AuNPs) was employed, using an alkaline solution of Pamoic acid (PA) (4,4′-methylene-bis (3-hydroxy-2-naphthalene carboxylic acid)). Since PA is insoluble in water, it can only be dissolved in alkaline media to act as both a capping and reducing reagent to form the AuNPs. Thus, monodispersed, stable, carboxylate-functionalized AuNPs were synthesized without applying thiol derivatives. KCZ was electrochemically studied using differential pulse voltammetry, square wave voltammetry and cyclic voltammetry on the modified carbon paste electrode surface. Under optimized conditions, at pH4.0 of 0.5M phosphate buffer solution (PBS), a linear response range for ketoconazole from 1.0 to 80.0μmolL−1 was achieved with a detection limit (LOD) of 0.1μmolL−1.

Application of Carbon Paste Electrode Modified with Carbon Nanofibres/Polyaniline/Platinum Nanoparticles as an Electrochemical Sensor for the Determination of Bezafibrate

AbstractThe present study deals with the development of an electrochemical sensor for quantitative determination of Bezafibrate (BZF) based on carbon nanofibers/polyaniline/platinum nanoparticles modified carbon paste electrode (CNF/PANI/Pt/CPE). BZF is a fibric acid derivative and is used largely in the treatment of lipid disorders. The nanocomposite was synthesized by in situ polymerization of aniline using ammonium persulphate and platinum nanoparticles were uniformly decorated on the CNF/PANI surface by reducing hexachloroplatinic acid using sodium borohydride. The electrochemical response of BZF at CNF/PANI/Pt/CPE was studied using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The above study resulted into significant improvement of the electrochemical signal towards the oxidation of BZF, revealing that the oxidation process is highly favorable at the surface of modified electrode. The anodic peak current Ip (μA) is found to be linearly dependent on BZF concentration in the range of 0.025 μM to 100 μM with a detection limit of 2.46 nM. The practical analytical utilities of the sensor were investigated by performing the experiments on synthetic pharmaceutical formulations, human blood serum and urine samples which offered good recovery, suggesting the high efficacy and authenticity of CNF/PANI/Pt/CPE sensor for BZF determination.

Electrochemical behavior of mefenamic acid at zinc oxide nanoparticles modified carbon paste electrode

Electrochemical oxidation of mefenamic acid at zinc oxide nanoparticles modified electrode was performed. Comparison of bare carbon paste electrode and zinc oxide nanoparticles modified carbon paste electrode, it was observed that the modified electrode has advantage of high sensitivity and selectivity with low detection limit. Effect of supporting electrolyte (phosphate buffer, I = 0.2 M) solution in the range, 3.0 – 11.2 pH was investigated and found that pH 5 is suitable for the investigations. In addition, effect of scan rate variations was studied to calculate some of the physiochemical properties. A differential pulse voltammetric method was developed for the analytical application. Low detection limit and quantification of 5.13 x 10 –10 and 1.17 x 10 –9 M respectively in the linearity range 1.0 x 10 –6 to 2.0 x 10 –8 shows that the developed method has a wide advantage over early reported methods. Further, the applicability of the method was investigated for pharmaceutical dose form and human urine samples

An enhanced sensing platform for clozapine at 2.0% silver doped TiO2 nanoparticles - A sensitive detection

Metal doped nanoparticles as a modifier have received attention in the development of electrochemical sensors and biosensors. In the current work, we established the electrochemical behaviour and detection of clozapine by utilizing 2.0% silver doped TiO2 nanoparticles modified carbon paste electrode (Ag-TiO2/CPE) at pH 4.2 by employing different voltammetric techniques. Modification enhances the electro-oxidation of clozapine with increased current intensity. The characterization of silver doped titanium dioxide nanoparticles was accomplished by utilizing X-ray diffraction (XRD), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscope (TEM). The influence of parameters like scan rate, pH, accumulation time, amount of the modifier and concentration on the peak current of the drug were studied. The effect of CLZ concentration variation was studied using square wave voltammetric (SWV) technique and got lowest detection limit compared to reported techniques. The fabricated sensor was employed for the determination of clozapine in pharmaceutical and biological samples

A Voltammetric Sensor Based on Spinel-Structured Copper Ferrite Nanoparticles Multiwalled Carbon Nanotubes Modified Carbon Paste Electrode for Determination of Dacarbazine

A simple and sensitive method was used to develop a novel sensor for determination of dacarbazine on the surface of multi-walled carbon nanotubes/CuFe2O4 nanoparticles modified carbon paste electrode (MWCNTs/CuFe2O4/CPE). Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy were used to investigate the electrochemical behavior of dacarbazine at the chemically modified electrode. According to the results, MWCNTs/CuFe2O4/CPE showed high electrocatalytic activity for dacarbazine oxidation, producing a sharp oxidation peak current at about +0.80 vs. Ag/AgCl reference electrode at pH 5.0. The peak current was linearly dependent on dacarbazine concentration over the range of 0.10–76.0 μmol L–1 with the detection limit (3σ) of 0.08 μmol L−1. In addition, chronoamperometry was also used to determine diffusion coefficient of dacarbazine at MWCNTs/CuFe2O4/CPE.

Nano-silica modified electrode as a sensor for the determination of mefenamic acid - A voltammetric sensor

Electrochemical oxidation of mefenamic acid was investigated at the surface of carbon paste electrode with silica nanoparticles as an modifier. The electrode surface was characterized by using SEM and TEM. Voltammetric behaviour of mefenamic acid was studied using cyclic voltammetric method. A nano silica modified carbon paste electrode was used to investigate the electrochemical oxidation of mefenamic acid. Comparison of bare carbon paste electrode and silica nanoparticles modified carbon paste electrode, it was observed that the modified electrode has advantage of high sensitivity and selectivity with low detection limit. Effect of supporting electrolyte (phosphate buffer, I = 0.2 M) solution in the range, 3.0 – 11.2 pH was investigated and found that pH 5 is suitable for the investigations. In addition, effect of scan rate variations was studied to calculate some of the physiochemical properties. An electrode reaction mechanism was proposed and differential pulse voltammetric method was developed for the analytical application. Further, the applicability of the proposed method was investigated for pharmaceutical dose form and human urine samples.

Electrocatalytic performance of a zinc sulphide nanoparticles-modified carbon paste electrode for the simultaneous determination of acetaminophen, guanine and adenine

The simultaneous electroanalysis of acetaminophen (AC), guanine (G) and adenine (A) was successfully achieved on the zinc sulphide nanoparticles-modified carbon paste electrode (ZnS NPs/CPE) in phosphate buffer solution (PBS).

A new sensing platform based on magnetic Fe3O4@NiO core/shell nanoparticles modified carbon paste electrode for simultaneous voltammetric determination of Quercetin and Tryptophan

In current study, electrochemical sensing electrode based on uniform three–dimensional (3D) flowerlike Fe3O4@NiO magnetic nanoparticles (MNPs) modified carbon paste electrode (Fe3O4@NiO/CPE) is introduced for simultaneous determination of Quercetin (Q) and Tryptophan (Trp).The Fe3O4@NiO nano-flowers were synthesized by solvothermal/decomposition method in a hierarchical architecture with microspheres of 70–80nm, and the outer shells consisted of several nano flakes with 10–20nm in thickness via a facile, cost effective technique. Various techniques were employed to thoroughly characterize of the sensor as well as the synthesizes magnetic nanoparticles, namely field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and voltammetry. Electrochemical studies revealed that the proposed sensor exhibited some major advantages, including high effective surface area, numerous reactive sites and excellent electrochemical catalytic activity toward oxidation of Q and Trp. Under the optimal conditions, the electrode showed linear responses for Q and Trp in wide ranges of concentrations, e.g. 0.08–60 and 0.1–120μM for Q and Trp, respectively. The estimated detection limits were 2.18 and 14.23nM for Q and Trp, respectively. This sensor displayed an excellent stability, selectivity, sensitivity and good reproducibility for the modified electrode, suggesting that the sensor was a promising one for the simultaneous determination of Q and Trp in human breast milk, cow milk and honey with an excellent recovery and without the interferences of coexisting substances.