Selective Voltammetric Sensor Research Articles

Determination of meloxicam in plasma samples using a highly selective and sensitive voltammetric sensor based on carbon paste electrodes modified by molecularly imprinted polymer nanoparticle–multiwall carbon nanotubes

A highly selective voltammetric sensor for the determination of meloxicam using a MIP@MWCNT–CPE is introduced.

A highly selective voltammetric sensor for nanomolar detection of mercury ions using a carbon ionic liquid paste electrode impregnated with novel ion imprinted polymeric nanobeads.

This work reports the preparation of a voltammetric sensor for selective recognition and sensitive determination of mercury ions using a carbon ionic liquid paste electrode (CILE) impregnated with novel Hg(2+)-ion imprinted polymeric nanobeads (IIP) based on dithizone, as a suitable ligand for complex formation with Hg(2+) ions. The differential pulse anodic stripping voltammetric technique was employed to investigate the performance of the prepared IIP-CILE for determination of hazardous mercury ions. The designed modified electrode revealed linear responses in the ranges of 0.5nM-10nM and 0.08μM-2μM with a limit of detection of 0.1nM (S/N=3). It was found that the peak currents of the modified electrode for Hg(2+) ions were at a maximum value in phosphate buffer of pH4.5. The optimized preconcentration potential and accumulation time were to be -0.9V and 35s, respectively. The applicability of the proposed sensor to mercury determination in waste water samples is reported.

An Electrochemical Nanosensor for Simultaneous Voltammetric Determination of Ascorbic Acid and Sudan I in Food Samples

In this work, we describe application of a high-sensitive electrochemical sensor for determination of ascorbic acid (AA) in the presence of high concentration of Sudan I in food samples. In the first step, we study synthesis and characterization of NiO/NPs with X-ray diffraction (XRD) method. In the second step, application of NiO/NPs describe in the preparation of carbon-paste electrode modified with (9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)-4-ethylbenzene-1,2-diol (DEDED) as a high-sensitive and selective voltammetric sensor for determination of AA and Sudan I. The electrocatalytic oxidation of AA at the modified electrode was investigated by cyclic voltammetry, chronoamperometry and square wave voltammetry (SWV). For the mixture containing AA and Sudan I, the peaks potential was well separated from each other. Their square wave voltammetrics peaks current increased linearly with their concentration at the ranges of 0.01–600 and 0.5–1,000 μM, with the detection limits of 0.006 and 0.2 μM, respectively. Finally, the proposed method was also examined as a selective, simple, and precise electrochemical sensor for the determination of AA and Sudan I in real samples such as fruit juices, fresh vegetable juice, chilli sauce and tomato sauce.

Highly sensitive and selective determination of thiocyanate using gold nanoparticles surface decorated multi-walled carbon nanotubes modified carbon paste electrode

Gold nanoparticles and multi-walled carbon nanotubes were used to fabricate a modified electrode, as a highly sensitive and selective voltammetric sensor, for the determination of thiocyanate. A fast and easy method for the fabrication of gold nanoparticles/multi walled carbon nanotube/carbon paste electrode (GNPs/MWCPE) by cyclic voltammetry was used. Scanning electron microscopy (SEM) image demonstrated that the gold nanoparticles deposited on MWCNTs/CPE, with an average size of 30nm. By combining the benefits of GNPs/MWCNTs and CPE, the resulted modified electrode exhibited outstanding electrocatalytic activity in terms of thiocyanate oxidation by giving much higher peak currents than those obtained for the unmodified CPE and also the MWCNTs-modified electrode. The effects of various experimental parameters on the voltammetric response of thiocyanate were investigated. At the optimum conditions the sensor has a linear response in the 0.01–200.0μmolL−1 concentration range, a very good detection sensitivity (2.9046μALμmol−1), and a low detection limit of 5×10−3μmolL−1 of thiocyanate. The proposed electrode was used to the determination of SCN– in saliva, urine and water samples and the results were found to be in good agreement with the values obtained by standard method.

A new copper doped montmorillonite modified carbon paste electrode for propineb detection

A new copper doped natural montmorillonite modified carbon paste electrode (Cu2+-Mt-CPE) was developed as a new highly sensitive and selective voltammetric sensor for on-line monitoring of propineb fungicide. The optimization and evaluation of the developed sensor were performed using square wave voltammetry and cyclic voltammetry techniques. The results show that the Cu2+ exchanged natural montmorillonite acts as an efficient electrocatalyst to detect propineb. Under the optimized conditions, a good sensitivity and selectivity to propineb was obtained at Cu2+-Mt-CPE with a low detection limit of about 1μM and wide linear range from 5 to 30μM. The developed method was successfully applied for the determination of propineb in river and sea water samples with a good recovery.

An electrochemical nanocomposite modified carbon paste electrode as a sensor for simultaneous determination of hydrazine and phenol in water and wastewater samples

In this study, we report preparation of a high sensitive electrochemical sensor for determination of hydrazine in the presence of phenol in water and wastewater samples. In the first step, we describe synthesis and characterization of ZnO/CNTs nanocomposite with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). In the second step, application of the synthesis nanocomposite describes the preparation of carbon paste electrode modified with N-(4-hydroxyphenyl)-3,5-dinitrobenzamide as a high sensitive and selective voltammetric sensor for determination of hydrazine and phenol in water and wastewater samples. The mediated oxidation of hydrazine at the modified electrode was investigated by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS). Also, the values of catalytic rate constant (k) and diffusion coefficient (D) for hydrazine were calculated. Square wave voltammetry (SWV) of hydrazine at the modified electrode exhibited two linear dynamic ranges with a detection limit (3σ) of 8.0nmolL(-1). SWV was used for simultaneous determination of hydrazine and phenol at the modified electrode and quantitation of hydrazine and phenol in some real samples by the standard addition method.

Graphene–platinum nanocomposite as a sensitive and selective voltammetric sensor for trace level arsenic quantification

A simple protocol for the chemical modification of graphene with platinum nanoparticles and its subsequent electroanalytical application toward sensitive and selective determination of arsenic has been described. Chemical modification was carried out by the simultaneous and sequential chemical reduction of graphene oxide and hexachloroplatinic acid in the presence of ethylene glycol as a mild reducing agent. The synthesized graphene–platinum nanocomposite (Gr–nPt) has been characterized through infrared spectroscopy, x-ray diffraction study, field emission scanning electron microscopy and cyclic voltammetry (CV) techniques. CV and square-wave anodic stripping voltammetry have been used to quantify arsenic. The proposed nanostructure showed linearity in the concentration range 10–100 nM with a detection limit of 1.1 nM. The proposed sensor has been successfully applied to measure trace levels of arsenic present in natural sample matrices like borewell water, polluted lake water, agricultural soil, tomato and spinach leaves.

A highly selective voltammetric sensor for sub-nanomolar detection of lead ions using a carbon paste electrode impregnated with novel ion imprinted polymeric nanobeads

This work reports the preparation of a voltammetric sensor for selective recognition and sensitive determination of lead ions using a carbon paste electrode (CPE) impregnated with novel Pb2+-ion imprinted polymeric nanobeads (IIP) based on dithizone, as a suitable ligand for complex formation with Pb2+ ions. The differential pulse anodic stripping voltammetric technique was employed to investigate the performance of the prepared IIP-CPE for determination of hazardous lead ions. The designed modified electrode was revealed linear responses in the ranges of 3.0×10−10 - 1.0×10−9mol dm−3 and 1.0×10−8 - 1.0×10−6mol dm−3 with a limit of detection (LOD) of 1.0×10−10mol dm−3 (S/N =3). It was found that the peak currents of the modified electrode for Pb2+ ions were at maximum value in acetate buffer of pH 4.0. The optimized preconcentration potential and accumulation time were to be -1.0V and 25 s, respectively. The applicability of the proposed sensor to lead determination in tap water and lipstick samples are reported.

Development of a selective and sensitive voltammetric sensor for propylparaben based on a nanosized molecularly imprinted polymer–carbon paste electrode

The design and construction of a selective voltammetric sensor for propylparaben (PP) in cosmetics by using a molecularly imprinted polymer (MIP) as recognition element was introduced. The MIP was synthesized by using PP as template and methacrylic acid as functional monomer and then incorporated in the carbon paste electrode as PP sensor. The molecularly imprinted polymer–carbon paste electrode (MIP–CPE) showed very high recognition ability in comparison to non-imprinted polymer–carbon paste electrode (NIP–CPE). It was shown that electrode washing after PP extraction, led to enhanced selectivity, without noticeably decreasing the sensitivity. Some parameters affecting sensor response were optimized, and a calibration curve was then plotted using differential pulse voltammetric (DPV) technique. A dynamic linear range of 1nM to 100nM was obtained. The detection limit of the sensor was calculated to be equal to 0.32nM. The imprinted electrode also displayed good selectivity for PP and selectivity coefficients were 2.29 and 1.66 for methylparaben (MP) and ethylparaben (EP) respectively. Structural analogs, such as phenol and p-hydroxybenzoic acid had almost no response. This sensor was used successfully for propylparaben determination in cosmetic sample.

Surface decoration of multi-walled carbon nanotubes modified carbon paste electrode with gold nanoparticles for electro-oxidation and sensitive determination of nitrite

In this paper, a highly sensitive and selective voltammetric sensor for the determination of nitrite is proposed. We described a fast and easy method for the fabrication of gold nanoparticles/multi-walled carbon nanotube/carbon paste electrode (GNPs /MWCPE) by one-step electrodeposition under controlled potential, the whole procedure takes only several minutes. Scanning electron microscopy (SEM) image demonstrated that the gold nanoparticles deposited on MWCNTs/CPE were uniform, with an average size of 30nm. By combining the benefits of GNPs/MWCNTs and CPE, the resulted modified electrode exhibited outstanding electrocatalytic activity in terms of nitrite oxidation by giving much higher peak currents than those found for the unmodified CPE and also the MWCNTs-modified electrode. The effect of various experimental parameters on the voltammetric response of nitrite was investigated. At the optimum conditions the sensor has a linear response in the 0.05–250.0µmolL−1 concentration range, a very good detection sensitivity (0.4177μALµmol−1), and a low detection limit of 1×10−2μmolL−1 of nitrite. Most common ions and many environmental organic pollutants do not interfere. The proposed chemically modified electrode was used to the determination of NO2- in several foodstuffs and water samples and the results were found to be consistent with the values obtained by the Griess protocol.

Development of a highly selective voltammetric sensor for nanomolar detection of mercury ions using glassy carbon electrode modified with a novel ion imprinted polymeric nanobeads and multi-wall carbon nanotubes

This work reports a voltammetric sensor for selective recognition and sensitive determination of mercury ions using glassy carbon (GC) electrode modified with a novel ion imprinted polymeric nanobeads (IIP) and multi-wall carbon nanotubes (MWCNTs). The ion imprinted polymers were prepared by dissolving the certain amount of mercury chloride and 5,10,15,20-tetrakis(3-hydroxyphenyl) porphyrin, in the presence of methacrylic acid and ethyleneglycol-dimethacrylate, using 2,2-azobisisobutyronitrile as initiator. The differential pulse anodic stripping voltammetric technique was employed to investigate the performance of the GC–IIP–MWCNTs modified electrode for determination of hazardous mercury ions. The designed modified electrode was shown a linear response in the range of 1×10−8–7.0×10−4M of Hg2+ ion with a detection limit of 5.0nM and sensitivity 4483.3nAμM−1. It was found that the peak currents of the modified electrode for Hg2+ ions were at maximum value in acetate buffer. The preconcentration potential and accumulation time were optimized to be −1.0V and 100s, respectively.

Determination of lamotrigine by using molecularly imprinted polymer–carbon paste electrode

By using a molecularly imprinted polymer (MIP) as a recognition element, construction of a high selective voltammetric sensor for lamotrigine (LTG) was performed. A LTG selective MIP and a non-imprinted polymer (NIP) were synthesized and then incorporated in the carbon paste (CP) electrodes. The sensor was applied for LTG determination using differential pulse voltammetric (DPV) method. The MIP–CP electrode showed very high recognition ability in comparison to NIP–CPE. Some parameters affecting the sensor response were optimized and then the calibration curve was plotted. Two dynamic linear ranges of 0.8–25 and 25–400nM were obtained. The detection limit of the sensor was calculated as 0.21nM. This sensor was used successfully for LTG determination in pharmaceutical preparations.

A sensitive and selective voltammetric sensor based on multiwall carbon nanotubes decorated with MgCr2O4 for the determination of azithromycin

In this report, we synthesized MgCr2O4 nanoparticles and then multiwall carbon nanotubes were decorated with the MgCr2O4 nanoparticles. The characteristics of the new materials were studied with different techniques such as transmission electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy and electrochemical impedance spectroscopy. The multiwall carbon nanotubes decorated with MgCr2O4 nanoparticles were used as a new mediator for voltammetric determination of azithromycin. The oxidation peak of azithromycin was appeared at a potential of about 720mV at a surface of the modified electrode. Differential pulse voltammetry exhibited two wide linear dynamic ranges of 0.25–4.0 and 4.0–10.0μmolL−1 azithromycin with a detection limit of 0.07μmolL−1 at pH 7.0. The influence of potential interfering compounds on the selectivity was studied. Finally, the modified electrode showed good sensitivity, selectivity and stability for the determination of azithromycin in real samples.

Selective and sensitive voltammetric sensor based on modified multiwall carbon nanotubes paste electrode for simultaneous determination of l-cysteine and folic acid

This paper reports the selective and sensitive voltammetric determination of l-cysteine in the presence of folic acid using ethynylferrocene modified carbon nanotubes paste electrode in 0.1 M phosphate buffer solution (pH 7.0). Using square wave voltammetry, we could measure l-cysteine and folic acid in one mixture independently from each other by a potential difference of about 410 mV for the first time. Square wave voltammetric peak current of l-cysteine and folic acid increased linearly with their concentrations in the ranges of 0.2–250.0 and 1.0–500.0 μmol L−1, respectively. The detection limits of 0.07 and 0.6 μmol L−1 were achieved for l-cysteine and folic acid, respectively. The proposed voltammetric sensor was successfully applied to the determination of l-cysteine and folic acid in real samples.

Selective Voltammetric Determination of Tartrazine in the Presence of Red 10B by Nanogold‐modified Carbon Paste Electrode

AbstractA nanogold modified carbon paste electrode (NG‐CPE) was fabricated and used as selective voltammetric sensor for determination of Tartrazine in the presence of Red 10B using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CHA). Electrochemical parameters including the diffusion coefficient (D), the electron transfer coefficient (aXXXXX), and the electron transfer number (n) were determined for the oxidation of Tartrazine. This modified electrode can be applied to simultaneous determination of Tartrazine and Red 10B, because of considerable decreases of anodic overpotentials for both compounds. After optimizing the experimental conditions, the anodic peak current of Tartrazine was linear to its concentration in the range of 0.05‐1.5 μmol l−1, and the detection limit was 0.017 μmol l−1 in phosphate buffer solution (PBS) at pH 4.0. The modified electrode has good stability and repeatability. It was applied to the determination of Tartrazine and Red 10B in soft drinks with satisfactory results.

Voltammetric Determination of Salicylic Acid by Molecularly Imprinted Film Modified Electrodes

A highly selective and sensitive voltammetric sensor for salicylic acid was introduced. The sensitive layer was prepared by electropolymerization of pyrrole on a glassy carbon electrode in the presence of salicylic acid as a template. The template could be removed effectively by a two-step method. The first step was fixed potential peroxide and the second step was alkali solution washing. A wide dynamic linear range of 5.0 × 10−9 to 1.0 × 10−3 mol · L−1 was obtained. The imprinted sensor could be easily fabricated and showed a stable and reproducible response without any influence of interferents commonly existing in drug combination samples.

New Modified-Multiwall Carbon Nanotubes Paste Electrode for Electrocatalytic Oxidation and Determination of Hydrazine Using Square Wave Voltammetry

The applications of p -aminophenol as a suitable mediator, as a sensitive and selective voltammetric sensor for the determination of hydrazine using a square wave voltammetric method were described. The modified multiwall carbon nanotubes paste electrode exhibited a good electrocatalytic activity for the oxidation of hydrazine at pH = 7.0. The catalytic oxidation peak currents showed a linear dependence of the peaks current to the hydrazine concentrations in the range of 0.5–175 μmol/L with a correlation coefficient of 0.9975. The detection limit (S/N = 3) was estimated to be 0.3 μmol/L of hydrazine. The relative standard deviations for 0.7 and 5.0 μmol/L hydrazine were 1.7 and 1.1%, respectively. The modified electrode showed good sensitivity and selectivity. The diffusion coefficient ( D = 9.5 × 10 −4 cm 2 /s) and the kinetic parameters such as the electron transfer coefficient (α = 0.7) of hydrazine at the surface of the modified electrode were determined using electrochemical approaches. The electrode was successfully applied for the determination of hydrazine in real samples with satisfactory results. This paper introduced a voltammetric sensor based on carbon nanotubes paste electrode for the determination of hydrazine using p -aminophenol. The sensor was successfully applied for the determination of hydrazine in water samples with satisfactory results.

Computational design and synthesis of a high selective molecularly imprinted polymer for voltammetric sensing of propazine in food samples

Using a molecularly imprinted polymer (MIP) as a recognition element, the design and construction of a high selective voltammetric sensor for propazine were introduced. A computational approach was developed to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparation. Having confirmed the results of computational method, three MIPs were synthesized with functional monomers methacrylic acid (MAA), acrylamide (AAM) and 4-vinylpyridine (4-VP). The results indicated that to prepare MIPs, acrylamide (AAM) is the best candidate. A propazine selective MIP and a nonimprinted polymer (NIP) were synthesized and then incorporated in the carbon paste electrodes (CPEs). The sensor was applied for propazine determination through the cathodic stripping voltammetric method. Two dynamic linear ranges of 0.01–1.0μmolL−1 and 1.0–55.0μmolL−1 were obtained. The detection limit of the sensor was calculated as 0.001μmolL−1. This sensor was used successfully for propazine determination in food samples.

Copper(II) determination by using carbon paste electrode modified with molecularly imprinted polymer

A high selective voltammetric sensor for Cu 2+ was introduced. Cu 2+ selective molecular imprinted polymers (MIPs) and non-imprinted polymers (NIPs) were synthesized and then used for carbon paste (CP) electrode preparation. The MIP, incorporated in the carbon paste electrode, functioned as selectively recognition element and pre-concentrator agent for Cu 2+ determination. The prepared electrode was used for Cu 2+ measurement by the three steps procedure, including analyte extraction in the electrode, electrode washing and electrochemical measurement of Cu 2+. The complete removal of Cu 2+ from polymer was confirmed by IR and EDX. The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. It was shown that electrode washing after Cu 2+ extraction led to enhanced selectivity. Some parameters affecting sensor response were optimized and then a calibration curve plotted. Two dynamic linear ranges of 7.0 × 10 −8 to 1 × 10 −6 mol/l and 1.0 × 10 −6 to 1 × 10 −4 mol/l were obtained. The detection limit of the sensor was calculated equal to 2.3 × 10 −8 mol/l. This sensor was used successfully for Cu 2+ determination in Yellow river water.

Preparation of electrochemical sensor for lead(II) based on molecularly imprinted film

A high selective voltammetric sensor for Pb2+ was introduced. The feasibility of utilizing strong interactions between Schiff bases and metal ion to prepare the molecularly imprinted polymers (MIPs) electrochemical sensor for Pb2+ in aqueous solutions was studied. Some parameters affecting sensor response were optimized and then a calibration curve was plotted. A dynamic linear range of 3.00×10−7 to 5.00×10−5mol/L was obtained. The redox process of Pb2+ on the imprinted electrode is controlled by surface reaction. The stability and the life of imprinted membrane were improved by storing into diluted Pb2+ ion solution. The proposed method was applied to determination of Pb2+ in the Yellow River.