Ionic Liquid Modified Carbon Paste Research Articles

Development of an efficient electrochemical sensor based on MoS2 nanosheets and ionic liquid modified carbon paste electrode for determination of ascorbic acid in the presence of vitamin B6

Development of an efficient electrochemical sensor based on MoS2 nanosheets and ionic liquid modified carbon paste electrode for determination of ascorbic acid in the presence of vitamin B6

Development of a highly sensitive voltammetric sensor for the detection of folic acid by using MoS2 and ionic liquid-modified carbon paste electrode.

Sensitive analytical determination of folic acid is important in clinical laboratories due to its versatile biological functions. A simple folic acid sensor was successfully fabricated based on two-dimensional transition metal dichalcogenide MoS2 modified carbon ionic liquid paste electrode (MoS2-CILPE). The electrochemical properties of the fabricated electrode were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry. The fabricated sensor displayed excellent electroactivity towards folic acid using CV. Under optimal conditions (0.1 M PBS (pH 7.0)), the DPV oxidation peak current was proportional to folic acid concentration in the range from 5.0 μM to 100.0 μM with an estimated limit of detection of 1.0 μM and limit of quantification of 5.0 μM. The ability of the sensor for routine analyses was demonstrated by the detection of folic acid present in folic acid tablets and urine samples with appreciable recovery values.

Electroanalytical application of Ag@POM@rGO nanocomposite and ionic liquid modified carbon paste electrode for the quantification of ciprofloxacin antibiotic

In this work, introduction of a sensitive electrochemical nanosensor based on carbon paste electrode (CPE) modified by silver decorated in polyoxometalate (POM), reduced graphene oxide (rGO) and ionic liquid (IL) was developed for measurement of ciprofloxacin (CIP). For this purpose, Ag@POM@rGO nanocomposite was firstly prepared and identified by various methods. The peaks of C 1 s, O 1 s, P 2p, Ag 3d and W 4f in the XPS spectra confirmed formation of the Ag@POM@rGO. The effects of Ag@POM@rGO and IL amounts, pH and scan rate were examined on the response of CIP electro-oxidation by Design-Expert software. Based on the obtained results, the modified electrode with 0.01 g of IL and 0.04 g of Ag@POM@rGO in phosphate buffer solution (0.1 M, pH 7.0) with at a scan rate of 0.07 V s−1 displayed the best electrochemical response. The oxidation overvoltage of CIP was significantly reduced compared to CPE and its oxidation current was increased dramatically. In the optimum situation, the calibration curve for CIP was obtained by SWV technique and limit of detection (LOD) and linear dynamic ranges (LDR) were attained to be 0.031 µM and 0.103–122.880 µM, respectively. The electron-transfer coefficient, catalytic rate constant and diffusion coefficient were obtained to be 0.855, 3.91 × 106 cm3 mol−1 s−1 and 2.52 × 10−5 cm2 s−1, respectively. Also, the practical application of Ag@POM@rGO-IL/CPE was considered by determining the concentration of spiked CIP in human plasma with good recovery. The planned procedure is easy, fast and inexpensive and might be used as an important analytical implement in quality control of the pharmaceutical industry.

Graphene Oxide-PAMAM Nanocomposite and Ionic Liquid Modified Carbon Paste Electrode: An Efficient Electrochemical Sensor for Simultaneous Determination of Catechol and Resorcinol.

In this paper, a simple strategy was proposed for the analysis of catechol by a carbon paste electrode (CPE) modified with graphene oxide-third generation of poly(amidoamine) dendrimer (GO/G3-PAMAM) nanocomposite and ionic liquid (IL). The synthesis of GO-PAMAM nanocomposite was confirmed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The prepared modified electrode (GO-PAMAM/ILCPE) exhibited good performance to detect catechol with a notable decrease in overpotential and increase in current compared with an unmodified CPE. Under optimum experimental conditions, GO-PAMAM/ILCPE electrochemical sensors indicated a lower limit of detection (LOD) of 0.034 μM and a linear response in the concentration range of 0.1 to 200.0 µM for the quantitative measurement of catechol in aqueous solutions. In addition, GO-PAMAM/ILCPE sensor exhibited an ability to simultaneously determine catechol and resorcinol. It can be found that catechol and resorcinol could be completely separated on the GO-PAMAM/ILCPE with the differential pulse voltammetry (DPV) technique. Finally, a GO-PAMAM/ILCPE sensor was utilized to detect catechol and resorcinol in water samples with recoveries of 96.2% to 103.3% and relative standard deviations (RSDs) of less than 1.7%.

A modified carbon paste electrode with N-rGO/CuO nanocomposite and ionic liquid for the efficient and cheap voltammetric sensing of hydroquinone in water specimens.

This paper reports a voltammetric sensor based on copper oxide nanoparticles on nitrogen-doped reduced graphene oxide nanocomposite (N-rGO/CuO)-ionic liquid modified carbon paste electrode (N-rGO/CuO-ILCPE) for determining the hydroquinone (HQ). The N-rGO/CuO was prepared by a facile protocol, followed by characterization via fourier transform-infrared (FT-IR) patterns, field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) analysis. The electrochemical behaviour was linearly symmetrical to various hydroquinone levels (1.0-600.0μM) with a narrow limit of detection (LOD=0.25μM). The diffusion coefficient was also estimated to be 4.1×10-6cm2/s. The N-rGO/CuO-ILCPE was impressively applicable in determination of hydroquinone in the real specimens.

Electrochemical immunosensor for the detection of anti-thyroid peroxidase antibody by gold nanoparticles and ionic liquid-modified carbon paste electrode

Electrochemical immunosensor for the detection of anti-thyroid peroxidase antibody by gold nanoparticles and ionic liquid-modified carbon paste electrode

Electrochemical determination of carbendazim in grapes and their derivatives by an ionic liquid-modified carbon paste electrode

Electrochemical determination of carbendazim in grapes and their derivatives by an ionic liquid-modified carbon paste electrode

A sensitive and simple method for voltammetric analysis of Sudan I as an azo dye in food samples using a Fe3O4-ZIF-67/ionic liquid modified carbon paste electrode

The present study developed a facile and fast electrochemical approach to sensitively analyze Sudan I using Fe3O4-ZIF-67 nanocomposite plus ionic liquid (IL). The carbon paste electrode (CPE) modified with Fe3O4-ZIF-67/IL exhibited an excellent electrochemical sensing performance to Sudan I. Compared with the unmodified CPE, Fe3O4-ZIF-67/ILCPE could significantly increase the peak current of Sudan I oxidation and decrease the oxidation overpotentials. Under the best experimental conditions, the sensor using differential pulse voltammetry (DPV) technique responded to Sudan I linearly (0.5 - 560 μM) with a low limit of detection (LOD) of 0.1 μM. Additionally, the applicability and effectiveness of our proposed method in sensing Sudan I present in food samples was confirmed by acceptable recovery rate (96.0 - 103.6 %).

A reliable electrochemical approach for detection of sulphite with Tl-doped in Mn3O4 nanostructures and ionic liquid-modified carbon paste electrode

ABSTRACT In this work, we have designed and developed a new electrochemical sensing platform to determine sulphite, with the aid of a carbon paste electrode modified with thallium doped Mn3O4 nanostructures and ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) (Tl-Mn3O4/IL/CPE). Electrochemical oxidation of sulphite at the Tl-Mn3O4/IL/CPE was investigated by the cyclic voltammetry (CV), linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and chronoamperometry (CHA) methods. The results of electrocatalytic activity proved that the Tl-Mn3O4/IL/CPE has electrocatalytic activity compared to unmodified CPE, Tl-Mn3O4/CPE and IL/CPE for sulphite oxidation. The experimental results showed the wide linearity range (0.03 to 235.0 μM) with lower value of detection (10.0 nM) for detection of sulphite. As expected, the proposed electrochemical sensor exhibits long time stability, excellent repeatability and reproducibility. In addition, this sensor exhibited high selectivity for the detection of sulphite in the presence of possible Interferences. The practical applicability of the modified electrode was examined in water samples with good recovery values. This facile and cost-effective method provides a novel strategy for monitoring of sulphite in real samples.

Electroanalytical performance of a β-cyclodextrin and ionic liquid modified carbon paste electrode for the determination of verapamil in urine and pharmaceutical formulation.

The analytical performance of sensitive and cost-effective electrochemical sensors based on ionic liquids (ILs) with the bis(trifluoromethylsulfonyl)imide anion, [NTf2]-, and the imidazolium cation with different alkyl chain lengths for electrochemical oxidation of verapamil (VER) was investigated. 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][NTf2]) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HMIM][NTf2]) were studied as possible materials for modification of a carbon paste electrode (CPE) for trace-level determination of VER. The experimental parameters including selection of the working electrode, the pH of working media, and the amount of CPE modifiers were investigated. Among them, the [EMIM][NTf2]-CPE with 4.3 wt% of IL was selected as the most appropriate for the square wave voltammetric (SWV) determination of VER at pH 5.0. Cyclic voltammetric studies showed that the electrochemical oxidation of VER was adsorption controlled. Consequently, the square wave adsorptive stripping voltammetric (SW-AdSV) parameters were optimized with Eacc = -0.4 V and tacc = 180 s as the most suitable for accumulation of VER on the electrode surface. The electroanalytical performance of the [EMIM][NTf2]-CPE was further improved by its in situ electrochemical modification with β-cyclodextrin (β-CD) and the linear concentration range of VER was from 0.006 to 0.129 μg mL-1; the relative standard deviation did not exceed 0.7%, and the evaluated limit of detection in model solution was 0.002 μg mL-1. The β-CD/[EMIM][NTf2]-CPE showed adequate selectivity towards VER in the presence of inorganic ions and interferents usually found in human urine. The proposed sensor was successfully applied for VER determination in a spiked human urine sample and pharmaceutical formulation with good repeatability and recovery.

Carbon Nitride Nanosheet and Myoglobin Modified Electrode for Electrochemical Sensing Investigations

Background: Carbon-based nanomaterials, especially carbon nitride (C3N4) has attracted tremendous interest in biosensor applications. Meanwhile, the mechanism of redox protein sensing and related electrocatalytic reactions can provide a valid basis for understanding the process of biological redox reaction. Objective: The aim of this paper is to construct a new electrochemical enzyme sensor to achieve direct electron transfer of myoglobin (Mb) on CILE surface and display electrocatalytic reduction activity to catalyze trichloroacetic acid (TCA) and H2O2. Methods: The working electrode was fabricated based on ionic liquid modified Carbon Paste Electrode (CILE) and C3N4 nanosheets were modified on the CILE surface, then Mb solution was fixed on C3N4/CILE surface and immobilized by using Nafion film. The as-prepared biosensor displayed satisfactory electrocatalytic ability towards the reduction of TCA and H2O2 in an optimum pH 7.0 buffer solution. Results: The results indicated that C3N4 modified electrode retained the activity of the enzyme and displayed quasi-reversible redox behavior in an optimum pH 7.0 buffer solution. The electrochemical parameters of the immobilized Mb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.27, the charge transfer coefficient (α) as 0.53 and the electrontransfer rate constant (ks) as 3.32 s-1, respectively. The Nafion/Mb/C3N4/CILE displayed outstanding electrocatalytic reduction activity to catalyze trichloroacetic acid and H2O2. Conclusion: The Nafion/Mb/C3N4/CILE displayed outstanding electrocatalytic reduction, which demonstrated the promising applications of C3N4 nanosheet in the field electrochemical biosensing.

Electrochemical detection of sulfasalazine in real samples by GO/Fe3O4@SiO2O3 nanostructure and ionic liquid modified carbon paste electrode

Electrochemical detection of sulfasalazine in real samples by GO/Fe3O4@SiO2O3 nanostructure and ionic liquid modified carbon paste electrode

A novel voltammetric sensor based on palladium nanoparticles/carbon nanofibers/ionic liquid modified carbon paste electrode for sensitive determination of anti-cancer drug pemetrexed

In the present study, for the first time, we develop a sensitive voltammetric technique for the determination of pemetrexed using Pd/carbon nanofibers/methyl (trioctyl)ammonium bis(trifluoromethylsulfonyl)imide ([M3OA]+[NTF2]−) ionic liquid modified carbon paste electrode in which Nafion was utilized as binder (CPE/Pd/CNF/[M3OA]+[NTF2]−/Nafion). Composite nanofibers were synthesized by electrospinning method and characterized by SEM, TEM, XRD and FT-IR and the synthesized ionic liquid was also investigated by FT-IR and UV–Vis. Square wave voltammetry (SWV) measurements were performed to investigate the electrochemical oxidation of pemetrexed using the proposed electrode in 0.1 M phosphate buffer solution at pH 6.0. Several parameters such as pH amount, scan rate and the type of supporting electrolyte were studied for pemetrexed oxidation. In addition, selectivity, repeatability, reproducibility and stability were also evaluated. Under optimized conditions, a linear concentration was detected in the range of 1.00–35.0 nM with a detection limit of 0.33 nM by SWV. The proposed sensor was successfully applied for the quantification of pemetrexed in cancerous human plasma, pharmaceutical and health urine samples.

Boron Nitride Nanosheet Modified Electrode: Preparation and Application to Direct Electrochemistry of Myoglobin

AbstractAn ionic liquid modified carbon paste electrode (CILE) was prepared with 1‐hexylpyridine hexafluorophosphate (HPPF6) and used as a substrate electrode. Then hexagonal boron nitride (BN) nanosheet, myoglobin (Mb) and Nafion were fixed on the electrode surface by coating method to get a new‐style chemically modified electrode (Nafion/Mb/BN/CILE). The morphology and crystal phase of BN nanosheet were characterized by SEM, TEM and XRD. UV‐Vis and FT‐IR results showed that Mb retained its original conformation in the composite modified film. In phosphate buffer solutions (PBS) with pH 3.0, cyclic voltammetry (CV) was performed to investigate the direct electrochemical behaviour of Mb. A pair of quasi‐reversible redox reaction peaks was obtained on the CV curve, proving that BN nanosheet had good biocompatibility and could accelerate electron transfer between Mb and electrode surface. Electrocatalytic reduction of trichloroacetic acid (TCA) was investigated, which was further applied to TCA detection. The catalytic reduction peak current at −0.355 V depended linearly on the TCA concentration in the range of 0.2∼30.0 mmol/L with the equation of Ipc (μA)=6.340 C (mmol/L)+0.305 (r=0.998), and the detection limit was 0.05 mmol/L (3 σ).

Electrochemical determination of 2,4-dichlorophenol at β-cyclodextrin functionalized ionic liquid modified chemical sensor: voltammetric and amperometric studies

A highly effective approach was developed for the specific detection of 2,4-dichlorophenol (2,4-DCP) in real samples, based on a cyclodextrin functionalized ionic liquid modified carbon paste electrode (β-CD-BIMOTs/CPE).

Highly sensitive voltammetric sensor based on NiO nanoparticle room temperature ionic liquid modified carbon paste electrode for levodopa analysis

This paper describes the development of 1-methyl-3-butylimidazolium chloride ionic liquid-NiO nanoparticle modified carbon paste electrode (MBICl/NiO/NPs/CPE) for the voltammetric determination of levodopa (l-DOPA) in real samples. We describe the synthesis and characterization of NiO/NPs with different methods such as transmission electron microscopy (TEM); energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The electrochemical oxidation of l-DOPA occurred in a pH-dependent 2e− and 2H+ process, and the electrode reaction followed a diffusion-controlled pathway. The oxidation peak potential of LDOPA on the MBICl/NiO/NPs/CPE appeared at 450mV, which was about 90mV decrease of the overpotential compared to that obtained on the traditional carbon paste electrode (CPE) and the oxidation peak current was increased for about 3.0 times. The electrochemical parameter such as charge transfer coefficient (α=0.73) was calculated. The linear response range and detection limit were found to be 0.7–900μmolL−1 and 0.4μmolL−1, respectively using the differential pulse voltammetry method (DPV). The results showed that the proposed sensor is highly selective, sensitive with a fast response for l-DOPA analysis.

Application of CdO nanoparticle ionic liquid modified carbon paste electrode as a high sensitive biosensor for square wave voltammetric determination of NADH

In this paper we report the synthesis and application of CdO nanoparticle (CdO/NPs) and 1,3-dipropylimidazolium bromide as high sensitive sensors for voltammetric determination of nicotinamide adenine dinucleotide (NADH) using carbon paste electrode. The cyclic voltammogram showed an irreversible oxidation peak at 0.68V (vs. Ag/AgClsat), which corresponded to the oxidation of NADH. Compared to common carbon paste electrode, the electrochemical response was greatly improved for NADH electrooxidation at a surface of CdO/NP modified ionic liquid carbon paste electrode (IL/CdO/NP/CPE). The linear response range and detection limit were found to be 0.09–750μmolL−1 and 0.05μmolL−1, respectively. Result shows that other physiological species did not interfere in the determination of NADH at the surface of the proposed sensor in the optimum condition. The proposed sensor was successfully applied for the determination of NADH in tap water, urine and pharmaceutical serum samples.

Sensitive Voltammetric Determination of Cadmium(II) with 8‐Hydroxyquinoline and Ionic Liquid Modified Carbon Paste Electrode

AbstractIn this paper 8‐hydroxyquinoline (HQ) and ionic liquid (IL) modified carbon paste electrode was fabricated and used for the sensitive determination of cadmium(II) with differential pulse anodic stripping voltammetry (DPASV). The modified electrode was prepared by the addition of HQ and IL 1‐ethyl‐3‐methylimidazoliam ethylsulphate as the modifiers into the traditional carbon paste mixture. Cd(II) was preconcentrated and reduced on the surface of the modified electrode at the potential of ‐1.0 V (vs. SCE) by the co‐contributions from the formation of HQ‐Cd(II) complex and the accumulation effect of IL. Then the reduced Cd on the electrode surface was reoxidized by DPASV with a sensitive oxidation peak appeared at ‐0.79 V (vs. SCE). Under the optimal conditions the oxidation peak current was proportional to the Cd(II) concentration in the range from 0.03 to 2.0 mol/L with the detection limit as 5.0 nmol/L (3σ). The proposed method was successfully applied to the water samples detection with the recovery in the range from 95.6% to 96.6%.

Ionic liquid modified carbon paste electrode and investigation of its electrocatalytic activity to hydrogen peroxide

. This paper reports on the preparation and advantages of novel amperometric biosensors in the presence of hydrophobic ionic liquid (IL), 1-methyl-3-butylimidazolium bromide ([MBIB]). Carbon paste biosensor has been constructed by entrapping horseradish peroxidase in graphite and IL mixed with paraffin oil as a binder. The resulting IL/graphite material brings new capabilities for electrochemical devices by combining the advantages of ILs composite electrodes. Amounts of H2O2 were amperometrically detected by monitoring current values at reduction potential (–0·15 V) of K3Fe(CN)6. Decrease in biosensor responses were linearly related to H2O2 concentrations between 10 and 100 μM with 2 s response time. Limit of detection of the biosensor were calculated to be 3·98 μM for H2O2. In the optimization studies of the biosensor some parameters such as optimum pH, optimum temperature, enzyme amount, interference effects of some substances on the biosensor response, reproducibility and storage stability were carried out. The promising results are ascribed to the use of an ionic liquid, which forms an excellent charge-transfer bridge and wide electrochemical windows in the bulk of carbon paste electrode.

Direct electrochemistry and electrocatalysis of myoglobin using an ionic liquid-modified carbon paste electrode coated with Co3O4 nanorods and gold nanoparticles

A nanohybrid biomaterial was fabricated by mixing Co3O4 nanorods, gold nanoparticles (Au-NPs) and myoglobin (Mb), and depositing it on the surface of a carbon paste electrode containing the ionic liquid N-hexylpyridinium hexafluorophosphate as the binder. UV–vis and FT-IR revealed the Mb in the composite film to have remained in its native structure. A pair of well-defined redox peaks appears in cyclic voltammograms and indicates direct electron transfer from the Mb to the underlying electrode. The results are attributed to the favorable orientation of Mb in the composite film, to the synergistic effects of Co3O4 nanorods and Au-NPs. The modified electrode shows excellent electrocatalytic ability towards the reduction of substrates such as trichloroacetic acid and nitrite, and displays good stability and reproducibility.