Ionic Liquid Carbon Paste Electrode Research Articles

Electrochemical preparation of polyaniline capped Bi2S3 nanocomposite and its application in impedimetric DNA biosensor

A highly sensitive impedimetric DNA biosensor based on rod-like bismuth sulfide nano (rBi2S3) and polyaniline (PANI) nanocomposite film modified ionic liquid-carbon paste electrode (IL-CPE) has been developed. The rBi2S3 particles were first dropt on IL-CPE that was constituted with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) and graphite powder, and then the PANI polymer was deposited on the surface of rBi2S3 through potentiodynamic polymerization using aniline as the source, forming the PANI capped Bi2S3 nanocomposite. The morphologies and electrocatalytic property of the composite were characterized by scanning electron microscopy (SEM) and electrochemical techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. The integrated advantages such as the large surface area, excellent electronic conductivity, easy to fabrication, and good biocompatibility make the electrode favorable for DNA immobilization and hybridization detection. It was found that remarkable increase of electrochemical impedance was observed after the probe DNA modified electrode was hybridized with the target DNA. The dynamic detection range was determined to be from 1.0×10−15 to 1.0×10−11M with a detection limit of 4.37×10−16M. The DNA biosensor also displayed good regeneration ability, reproducibility and stability.

Electrocatalytic oxidation of uric acid on a carbon ionic liquid paste electrode

Electrocatalytic oxidation of uric acid on a carbon ionic liquid paste electrode

Evaluation of ZnO nanoparticle ionic liquid composite as a voltammetric sensing of isoprenaline in the presence of aspirin for liquid phase determination

In the present work an easy-to-make and sensitive sensor based on ZnO nanoparticle (ZnO/NP) ionic liquid (IL) composite for voltammetric sensing of isoprenaline (ISN) in real samples was developed. The synthesized nanoparticle was characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The modified ZnO/NP ionic liquid carbon paste electrode (ZnO/NP/IL/CPE) was used as an electrochemical sensor for the determination of trace amounts of ISN. The anodic peaks of ISN and aspirin (ASP) in their mixture can be well separated. At pH5.0 the two peaks are separated ca. 0.56 and 0.98V, respectively; hence ISN can be determined in the presence of ASP and more than 2.6 times of the current excess of ISN. The square wave (SW) voltammogram peak current of ISN and ASP increased linearly with their concentration in the ranges of 0.3–320μmolL−1 ISN and 0.7–950μmolL−1 ASP. The detection limits for ISN and ASP were 0.09 and 0.3μmolL−1, respectively. The suggestion sensor has been successfully applied for the assay of the above compounds in real samples such as drug and urine.

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.

ZnO Nanoparticle Ionic Liquids Carbon Paste Electrode as a Voltammetric Sensor for Determination of Sudan I in the Presence of Vitamin B6 in Food Samples

Room-temperature ionic liquid n-hexyl-3-methylimidazolium hexafluoro phosphate as a binder and ZnO nanoparticle (ZnO/NPs) as a sensor were used to construct a new ZnO/NPs carbon ionic liquid paste electrode (ZnO/NPs/IL/CPE), which exhibited enhanced electrochemical behavior as compared with the traditional carbon paste electrode with paraffin for electrooxidation of Sudan I. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of Sudan I and vitamin B6. The peaks current of square wave voltammograms (SWV) of Sudan I and vitamin B6 increased linearly with their concentration in the ranges of 0.01–400 μM Sudan I and 0.5–800 μM vitamin B6. The detection limits for Sudan I and vitamin B6 were 0.008–0.2 μM, respectively. The modified electrode has been successfully applied for the assay of Sudan I and vitamin B6 in food samples.

A voltammetric biosensor based on ionic liquid/NiO nanoparticle modified carbon paste electrode for the determination of nicotinamide adenine dinucleotide (NADH)

Herein we report a NiO/nanoparticles (NiO/NPs) modified carbon ionic liquid paste electrode (IL/NiO/NPs/CPE) was fabricated and used to investigate the electrochemical behavior of NADH in aqueous solution. The proposed sensor was prepared by mixing hydrophilic ionic liquid 1-methyl-3-butylimidazolium bromide, NiO/NPs, graphite powder and liquid paraffin together. The oxidation peak potential of NADH at the surface of the ionic liquid NiO/NPs carbon paste electrode appeared at 635mV, which was about 70mV lower than the oxidation peak potential at the surface of traditional carbon CPE under similar conditions. On other hand, the oxidation peak current was increased to about four times at the surface of IL/NiO/NPs/CPE compared to CPE. The linear response range and detection limit were found to be 0.03–900μmolL−1 and 0.009μmolL−1, respectively. IL/NiO/NPs/CPE was successfully applied for the determination of NADH in real samples such as water, serum and urine. The results showed that the proposed method is highly selective, sensitive with a fast response for NADH analysis.

Fabrication of gallium hexacyanoferrate modified carbon ionic liquid paste electrode for sensitive determination of hydrogen peroxide and glucose

Gallium hexacyanoferrate (GaHCFe) and graphite powder were homogeneously dispersed into n-dodecylpyridinium hexafluorophosphate and paraffin to fabricate GaHCFe modified carbon ionic liquid paste electrode (CILPE). Mixture experimental design was employed to optimize the fabrication of GaHCFe modified CILPE (GaHCFe-CILPE). A pair of well-defined redox peaks due to the redox reaction of GaHCFe through one-electron process was observed for the fabricated electrode. The fabricated GaHCFe-CILPE exhibited good electrocatalytic activity towards reduction and oxidation of H2O2. The observed sensitivities for the electrocatalytic oxidation and reduction of H2O2 at the operating potentials of +0.8 and −0.2V were about 13.8 and 18.3mAM−1, respectively. The detection limit (S/N=3) for H2O2 was about 1μM. Additionally, glucose oxidase (GOx) was immobilized on GaHCFe-CILPE using two methodology, entrapment into Nafion matrix and cross-linking with glutaraldehyde and bovine serum albumin, in order to fabricate glucose biosensor. Linear dynamic rage, sensitivity and detection limit for glucose obtained by the biosensor fabricated using cross-linking methodology were 0.1–6mM, 0.87mAM−1 and 30μM, respectively and better than those obtained (0.2–6mM, 0.12mAM−1 and 50μM) for the biosensor fabricated using entrapment methodology.

A novel nanosensor based on Pt:Co nanoalloy ionic liquid carbon paste electrode for voltammetric determination of vitamin B9 in food samples

In this work we describe a novel nanoalloy (Pt:Co) room temperature ionic liquid (RTIL) modified carbon paste electrode as a high sensitive sensor for voltammetric determination of vitamin B9 in food samples. The sensor exhibits an enhanced effectiveness for the electro-oxidation of vitamin B9 in aqueous solution. The oxidation peak potential for this matter at a surface of the ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) Pt:Co carbon paste electrode (Pt:Co/IL/CPE) appeared at 685 mV that was about 110 mV lower than the oxidation peak potential at the surface of the traditional carbon paste electrode (CPE) under similar condition. The mechanism of the electro-oxidation process on the surface of the modified electrode was analyzed. Square wave voltammetry (SWV) was applied as a very sensitive electrochemical method for the determination of sub-micro-molar amounts of vitamin B9. The linear response range and detection limit were found to be 1.0 × 10−7 to 5.0 × 10−4 M and 4.0 × 10−8 M, respectively. The prepared modified electrode shows several advantages such as simple preparation method, high stability, high sensitivity, and excellent catalytic activity, long-term stability and remarkable voltammetric reproducibility for eletrooxidation of vitamin B9. The proposed sensor was successfully applied for the determination of vitamin B9 in food samples.

New copper complexes incorporated with the one-step preparation of ionic liquid carbon paste electrode for highly selectively reducing hydrogen peroxide

New copper complex compounds composed of 2,4,6-tris(2-pyridylmethylamino)-1,3,5-triazine (TPMATA) and CuCl2/CuSO4 in water or ionic liquid (IL) were prepared. Two approaches were used to fix the copper complexes to the IL carbon paste electrodes through our previous one-step method. IL shows its advantage over the traditional organic binder paraffin oil because the electrodes demonstrated much higher activity towards hydrogen peroxide reduction. After introducing TPMATA–CuCl2 dissolved in IL to the electrode, the electrode shows the best current response and selectivity to hydrogen peroxide reduction.

A voltammetric sensor based on NiO/CNTs ionic liquid carbon paste electrode for determination of morphine in the presence of diclofenac

A novel ionic liquid modified NiO/CNTs carbon paste electrode (IL/NiO/CNTCPE) had been fabricated by using hydrophilic ionic liquid 1-methyl-3-butylimidazolium chloride [MBIDZ]Cl as a binder. The cyclic voltammogram showed an irreversible oxidation peak at 0.61V (vs. Ag/AgClsat), which corresponded to the oxidation of morphine. Compared to common carbon paste electrode, the electrochemical response was greatly improved for morphine electrooxidation. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of morphine and diclofenac. Detection limit of morphine was found to be 0.01μM using square wave voltammetry (SWV) method. The proposed sensor was successfully applied for the determination of morphine in human urine and pharmaceutical samples.

Construction of a carbon ionic liquid paste electrode based on multi-walled carbon nanotubes-synthesized Schiff base composite for trace electrochemical detection of cadmium

A simple, highly sensitive and selective carbon nanocomposite electrode has been developed for the electrochemical trace determination of cadmium. This sensor was designed by incorporation of multi-walled carbon nanotubes (MWCNTs) and a new synthesized Schiff base into the carbon paste ionic liquid electrode (CPEIL) which provides remarkably improved sensitivity and selectivity for the electrochemical stripping assay of Cd(II). The detection limit of the method was found to be 0.08μgL−1 (S/N=3) that is lower than the maximum contaminant level of Cd(II) allowed by the Environmental Protection Agency (EPA) in standard drinking waters. The proposed electrode exhibits good applicability for monitoring Cd(II) in various real samples.

ZnO nanoparticle-modified ionic liquid-carbon paste electrodefor voltammetric determination of folic acid in food and pharmaceutical samples

In this work, a ZnO/nanoparticles (NPs) modified carbon ionic liquid paste electrode (ZnO/NP/CILPE) was fabricated and used to investigate the electrochemical behavior of folic acid. ZnO/NP/CILPE was prepared by mixing hydrophilic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim]-[PF6])), ZnO/NPs, graphite powder, and liquid paraffin together. The fabricated ZnO/NP/CILPE showed great electrocatalytic ability to the oxidation of folic acid, and an irreversible oxidation peak appeared at 0.75 V (vs. Ag/AgCl) with improved peak current. Under the optimized conditions of pH 9.0, the plot of peak current vs. folic acid concentration consisted of two linear segments with slopes of 1.776and 0.033 μA/μM in the concentration ranges of 0.05–1.5 μM and 1.5–550.0 μM, respectively. The detection limit was 0.01 μM (3σ). The proposed sensor was successfully applied for the determination of folic acid in fortified food and pharmaceutical samples.

Application of poly(acridine orange) and graphene modified carbon/ionic liquid paste electrode for the sensitive electrochemical detection of rutin

A carbon/ionic liquid paste electrode (CILPE) prepared by 1-hexylpyridinium hexafluorophosphate as the binder was used as the substrate electrode. A layer of graphene oxide (GO) film was cast on CILPE surface (GO/CILPE) and the electropolymerization of acridine orange (AO) on electrode was further realized by cyclic voltammetry in the potential range from −1.40V to 1.40V, which could simultaneously reduce GO to graphene (GR) electrochemically. The fabricated PAO-GR/CILPE exhibited good electrochemical performances with higher conductivity and lower electron transfer resistance. Electrochemical behaviors of rutin were further investigated on the modified electrode in 0.1mol/L pH 2.0 phosphate buffer solution by cyclic voltammetry with a pair of well-defined redox peaks appeared. The peak-to-peak separation (ΔEp) was calculated as 0.076V, which proved a fast quasi-reversible electron transfer process and the electrochemical parameters of rutin on PAO-GR/CILPE were calculated. Under the optimal conditions, the linear relationship between the oxidation peak current of rutin and its concentration was obtained in the range from 0.03 to 800.0μmol/L with the detection limit as 8.33nmol/L (3σ). The PAO-GR/CILPE showed good selectivity, stability and reproducibility, which was further applied to detect rutin tablet samples with satisfactory results.

High sensitive voltammetric sensor based on Pt/CNTs nanocomposite modified ionic liquid carbon paste electrode for determination of Sudan I in food samples

In this work, a simple and high sensitivity electrochemical sensor was developed to determine Sudan I based on Pt/CNTs nanocomposite ionic liquid modified carbon paste electrode (Pt/CNTs/ILCPE) using cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) methods. The novel sensor exhibited an obviously catalytic activity towards the oxidation of Sudan I, which can be confirmed by the increased oxidation peak current and the decreased oxidation peak potential when compared with the bare carbon paste electrode (CPE). The electron transfer coefficient (α), diffusion coefficient (D), and charge transfer resistance (Rct) of Sudan I at the modified electrode were calculated. The linear response range and detection limit were found to be 0.008–600μmolL−1 and 0.003μmolL−1, respectively. Other species did not interfere with the determination of Sudan I at a surface of propose sensor in the optimum condition. The proposed sensor was successfully applied for the determination of Sudan I in food samples with satisfactory results.

A fast and sensitive nanosensor based on MgO nanoparticle room-temperature ionic liquid carbon paste electrode for determination of methyldopa in pharmaceutical and patient human urine samples

In this study, we describe an ionic liquid–MgO nanoparticle modified carbon paste electrode (MgO/NPs/IL/CPE) was used as a simple, fast, and sensitive tool for the investigation of the electrochemical oxidation of methyldopa (MDOP) using voltammetric methods. The MgO/NPs was characterized with different methods such as TEM, SEM, and XRD. The oxidation peak potential of the MDOP at a surface of MgO/NPs/IL/CPE appeared at 450 mV that was about 100 mV lower than the oxidation peak potential at the surface of the traditional carbon paste electrode (CPE) under similar conditions. The electro-oxidation of MDOP occurred in a pH-dependent 2e− and 2H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under optimal conditions at pH 7.0, the anodic peak currents increased linearly with the concentration of MDOP in the range of 0.08–380 μmol L−1 with a detection limit of 0.03 μmol L−1 (3σ). The proposed sensor was successfully applied to the determination of MDOP in real samples such as drug and urine.

A novel electrochemical sensor based on ZnO nanoparticle and ionic liquid binder for square wave voltammetric determination of droxidopa in pharmaceutical and urine samples

Synthesis and application of ZnO nanoparticles (Zn/NPs) and 1-butyl-3-methylimidazolium hexafluoro phosphate as high sensitive sensors for voltammetric determination of droxidopa (DXP) using carbon paste electrode has been reported for the first time. The synthesized nanoparticles were characterized by different methods such as TEM, SEM and XRD. The electrochemical oxidation of DXP on the new ZnO/NPs ionic liquid carbon paste electrode (ZnO/NPs/IL/CPE) has been carefully studied. The experimental results suggested that the modified electrode promoted electron transfer reaction for the oxidation of DXP. Under the optimized conditions of pH 7.0, the plot of peak current vs. DXP concentration consisted of two linear segments with slopes of 0.4733 and 0.0177μAμmol−1L in the concentration ranges 0.4–5.0μmolL−1 and 5.0–310.0μmolL−1, respectively. The detection limit was 0.15μmolL−1. The proposed method was successfully applied for the determination of DXP in tablet, serum and urine samples.

Electrochemical behavior of morphine at ZnO/CNT nanocomposite room temperature ionic liquid modified carbon paste electrode and its determination in real samples

In this paper we report synthesis and application of ZnO/CNT nanocomposite and 1-methyl-3-butylimidazolium bromide as high sensitive sensors for voltammetric determination of morphine using carbon paste electrode. The ZnO/CNT nanocomposite was characterized with different methods such as TEM, SEM and XRD. The electrochemical oxidation of morphine on the new ZnO/CNTs ionic liquid carbon paste electrode (ZnO/CNTs/IL/CPE) was carefully studied. The oxidation peak potential of morphine on the ZnO/CNTs/IL/CPE appeared at 520mV, which was about 75mV decrease of the overpotential compared to that obtained on the traditional carbon paste electrode (CPE) and the oxidation peak current was increased for about 5.5 times. The electrochemical parameter of morphine on the ZnO/CNTs/IL/CPE was calculated with the charge transfer coefficient (α). Based on the relationship of the oxidation peak current and the concentration of morphine a sensitive analytical method was established with cyclic voltammetry. The linear range for morphine determination was in the range from 0.1 to 700μmolL−1 and the detection limit was calculated as 0.06μmolL−1 (3σ). Finally, the proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of morphine in real samples such as urine and ampoule.

A novel and simple electrochemical sensor for electrocatalytic reduction of nitrite and oxidation of phenylhydrazine based on poly (o-anisidine) film using ionic liquid carbon paste electrode

In this study, nitrite electroreduction and phenylhydrazine electrooxidation were investigated on poly(o-anisidine) formed by cyclic voltammetry at the surface of ionic liquid carbon paste electrode. The films were characterized by cyclic voltammetry and scanning electron microscopy (SEM) and were contrasted with poly(o-anisidine) prepared under identical conditions in the absence of ionic liquid in carbon paste electrode. This carbon paste modified electrode exhibits a good electrocatalytic capability (via an EC’ mechanism) for both electrooxidation and electroreduction of some important molecules. The obtained results showed that the catalytic oxidation peak currents of phenylhydrazine and catalytic reduction peak currents of nitrite at the surface of this simple (unfunctionalized) polymeric electrode were linearly dependent on their concentrations. Electrode was successfully applied for determination of nitrite and phenylhydrazine in real samples.

Determination of Inorganic Phosphate in Environmental Water Using Cobalt Film Modified Ionic Liquid-Carbon Paste Electrode

<abstract><title><italic>Abstract.</italic></title> In this work, a novel phosphate ion-selective sensor based on a cobalt thin-film modified ionic liquid-carbon paste electrode was developed. This sensing electrode was prepared by electrodeposition of cobalt nanoparticles onto the surface of an ionic liquid-carbon paste electrode. Cyclic voltammetry and scanning electron microscopy were employed to characterize the cobalt film. With the unique properties of the cobalt nanostructure film, the developed electrode exhibited very attractive potentiometric characteristics for phosphate analysis. Several influencing parameters were investigated in detail, including dissolved oxygen and solution stirring rate. The developed electrode showed a wide linear range from 5 × 10^-6 to 1 × 10^-1 mol L^-1 with a response slope of -55.2 mV decade^-1. The detection limit of the electrode for phosphate was 1 × 10^-6 mol L^-1. Furthermore, the proposed electrode was applied to determine phosphate in environmental water samples. The detection results were in good agreement with those obtained by spectrophotometry. Dissolved oxygen exhibited no obvious effects on real sample analysis. The results suggested that the cobalt thin-film modified ionic liquid-carbon paste electrode was sensitive, reliable, and effective for the potentiometric determination of inorganic phosphate.

Fabrication and Application of a Sensitive and Highly Stable Copper Hexacyanoferrate Modified Carbon Ionic Liquid Paste Electrode for Hydrogen Peroxide and Glucose Detection

AbstractA three‐factor mixture design and response surface methodology were employed to find the optimal weight ratio of graphite powder, n‐dodecylpyridinium hexafluorophosphate and paraffin for the fabrication of a copper hexacyanoferrate modified carbon ionic liquid paste electrode (CuHCFe‐CILPE). The fabricated sensor showed electrocatalytic activity towards oxidation and reduction of hydrogen peroxide. It also was observed that the electrocatalytic activity for hydrogen peroxide oxidation was much higher than the electrocatalytic activity for hydrogen peroxide reduction. Glucose oxidase was then successfully immobilized on the surface of the proposed sensor to examine the possibility of using CuHCFe‐CILPE for the biosensor fabrication.