Modified Carbon Ionic Liquid Electrode Research Articles

Fabrication of graphitic carbon nitride and black phosphorene composite based electrochemical sensor and application for sensitive determination of quercetin

A novel electrochemical method for sensitive detection quercetin (QU) was constructed with graphitic carbon nitride (g-C3N4) and black phosphorene (BP) composite (g-C3N4@BP) modified carbon ionic liquid electrode (CILE) as signal amplified interface. g-C3N4@BP was synthesized by a hydrothermal method with the characteristics investigated by SEM, XPS, FT-IR, XRD and electrochemical methods. Electrochemical behaviors of QU on the modified electrode (g-C3N4@BP/CILE) was investigated with the electrochemical parameters calculated and the experimental conditions optimized. The excellent electroanalytical result of QU was realized with the linear concentration range from 5.0 nmol/L to 90.0 µmol/L and a lower detection limit of 1.7 nmol/L (3σ). It was proved that the composite exhibited the synergistic effect of BP and g-C3N4 with more active sites, porous structure, large specific surface area, good electrical conductivity and strong electrocatalytic activity. The g-C3N4@BP/CILE was successfully used to detect the practical drug and food samples with satisfactory recoveries.

Electrochemical Determination of Rutin on a Gold Microsphere—Taro Stalk Porous Carbon Modified Carbon Ionic Liquid Electrode (CILE)

As an abundant, inexpensive, and renewable biomass raw material, taro [Colocasia esculenta (L.) Schott] stalks were employed as a simple biochar template due to their porous structure. A composite composed of gold microsphere and taro stalk derived porous carbon (Au-MS@TSPC) was used to construct an electrochemical sensor for the sensitive determination of rutin. Under the optimized conditions, the sensor exhibited a wide linear range from 0.12 to 10.0 μmol·L−1 with a detection limit of 0.0265 μmol·L−1. The sensor demonstrated good selectivity and was applied to the determination of rutin in human serum with recoveries from 94.0% to 105.8%. The fabrication of Au-MS@TSPC in this study provides a promising approach for the subsequent utilization of taro stalks.

Fabrication of Myoglobin-Sodium Alginate-Graphene Composite Modified Carbon ionic liquid electrode via the Electrodeposition Method and Its Electrocatalysis toward Trichloroacetic Acid

Fabrication of Myoglobin-Sodium Alginate-Graphene Composite Modified Carbon ionic liquid electrode via the Electrodeposition Method and Its Electrocatalysis toward Trichloroacetic Acid

Direct Electrochemistry of Hemin on Graphdiyne Modified Carbon Ionic Liquid Electrode and Electrocatalysis to Bromate

Direct Electrochemistry of Hemin on Graphdiyne Modified Carbon Ionic Liquid Electrode and Electrocatalysis to Bromate

A new electrochemical sensor based on green synthesized CuO nanostructures modified carbon ionic liquid electrode for electrocatalytic oxidation and monitoring of l-cysteine

In this study, we introduced a new carbon composite electrode modified with green synthesized CuO nanostructures (CuO-NSs) for sensitive l-cysteine determination. We applied a cost-effective and green method to synthesize CuO-NSs using Terminalia catappa leaf extract as a reducer and stabilizer without other additives. The CuO nanostructures were characterized by Ultraviolet–visible spectroscopy (UV–vis), X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FE-SEM-EDX) and elemental mapping, transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Electrochemical techniques such as cyclic voltammetry and amperometry were applied to investigate the electrochemical performance of the composite electrode for cysteine (l-Cys) electrooxidation. The composite electrode showed a noticeable shift in the electrooxidation peak potential of l-Cys over the conventional electrodes and a stable and sensitive electrochemical response by providing active sites and effective electron transfer pathways. Effects of various parameters such as pH of the solution, the amount of modifier, and scan rate were investigated on the electrochemical behavior of l-Cys. Under the optimal experimental conditions, the fabricated l-Cys sensor showed a linear relationship over an extensive concentration range of 10.0 µM to 5000.0 µM (R2 = 0.998) with a limit of detection (LOD) of 0.51 µM at physiological conditions (pH = 7.0). In addition, the composite electrode displayed high selectivity, good average reproducibility (RSD = 2.45 %), and applicability in the real sample on the l-Cys detection. The green, fast, simple, and cost-effective synthesis of CuO-NSs and good electrocatalytic activity of the modified electrode reveal good use of the prepared sensor to detect l-Cys.

Porous biomass carbon and gold nanoparticles modified electrode for myoglobin direct electrochemistry and electrocatalysis

AbstractIn this paper, a stable porous biomass carbon (BC) and gold (Au) nanoparticles modified carbon ionic liquid electrode (CILE) was prepared for the investigation of direct electrochemistry and electrocatalysis of myoglobin (Mb). BC was synthesized via pyrolysis of Hainan's natural tropical plant Lagerstroemia indica leaves, which was modified on the surface of CILE with Au nanoparticles further electrodeposited on the electrode surface. Then, Mb was cast on the nanocomposite‐modified electrode to obtain an electrochemical sensing platform with Nafion film (Nafion/Mb/Au−BC/CILE). Direct electrochemistry of Mb on the modified electrode was investigated with appearance of a pair of enhanced redox peaks, indicating direct electron transfer rate of Mb was accelerated due to the presence of Au−BC nanocomposite. Au−BC nanocomposite exhibited high conductivity, good biocompatibility, and large surface area, which was beneficial for electron transfer of Mb. The Mb modified electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid (TCA) and sodium nitrite (NaNO2), which was further used to establish a new electroanalytical method with satisfied sensitivity in real samples analysis.

A novel self-assembled gold nanoparticles-molecularly imprinted modified carbon ionic liquid electrode with high sensitivity and selectivity for the rapid determination of bisphenol A leached from plastic containers

In the present work, a new nanocomposite, reduced graphene oxide (rGO) decorated by mercaptamine- gold nanoparticles (AuNPs-MCA-rGO) was synthesized for the first time by a facile hydrothermal method. The carbon ionic liquid electrode (CILE) was modified by AuNPs-MCA-rGO and molecular imprinted polymer (MIP) to sensitive and selective electrochemical microanalysis of bisphenol A (BPA). The modifier provides a large surface area, selective sites and exhibited a rapid electron transport rate for the bisphenol A (BPA). In this research, a new electrochemical microcell with a volume of 25 µL was fabricated which can reduce drastically the required volume of analysis. This advantage leads to less use of chemicals and the possibility of micro sample analyzing. Therefore, the method is presented as a economical electro-analytical method. Under the optimized conditions, the linear response was observed for BPA concentration in the range of 4.0 × 10−9 to 1.8 × 10−5 M by cyclic voltammetry (CV). The detection limit of the method was obtained as 1.1 × 10−9 M by CV. Because of imprinted polymers in composition of modifier, the proposed sensor shows great potential applications in biomarker detection, food safety testing and environmental monitoring. It was used for the quantitative determination of BPA leached from plastic containers for food storage (PVC food package, PC baby bottle, and PC water bottle).

Development of an Electrochemical DNA Biosensor Based on Gold Nanoparticles and Thiol Graphene Nanocomposite for Detection of a Specific nuc Gene from Staphylococcus aureus

Background:: An electrochemical DNA biosensor based on gold nanoparticles (AuNPs) and thiol graphene (TGR) nanocomposite modified carbon ionic liquid electrode (CILE) was developed to detect a specific nuc gene of Staphylococcus aureus, which was further used in the analysis of PCR amplification samples from unfrozen pork. Objective:: The development of a DNA biosensor derived from AuNPs-coated TGR could be used as a novel sensing method for the detection of specific ssDNA sequences in biological and clinical samples. Methods: The electrochemical properties of modified CILE electrodes were determined by cyclic voltammetry and electrochemical impedance spectroscopy, and the electrochemical performances of the biosensor were investigated by differential pulse voltammetry. Results:: This gene sensor was able to detect the specific nuc gene from Staphylococcus aureus over the concentration range from 1.0×10-15 mol L-1 to 1.0×10-6 mol L-1 with a limit of detection of 4.5×10-16 mol L-1 (3σ), and it was applied in the detection of Staphylococcus aureus in an unfrozen pork sample after PCR amplification of the nuc gene with satisfactory results. Conclusion:: This gene biosensor showed high sensitivity and good selectivity, wide detection range and low detection limit, which demonstrated an effective tool to detect specific nuc gene sequences of Staphylococcus aureus.

Au-Pt@Biomass porous carbon composite modified electrode for sensitive electrochemical detection of baicalein

A gold and platinum bimetal decorated biomass porous carbon (Au-Pt@BPC) composite was synthesized by carbonization of oyster mushroom and solvothermal method, which was applied to the electrode modification and electrochemical detection of baicalein. The structural and elemental aspects of Au-Pt@BPC were analyzed by X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and Raman spectrum. The Au-Pt@BPC modified carbon ionic liquid electrode (CILE) was prepared as working electrode for the detection of baicalein. Baicalein exhibited a pair of redox peak on cyclic voltammograms with enhanced peak currents, which proved the positive effects of the composite including the high conductivity of bimetal, the catalytic activity of noble metal and the large-surface of porous carbon with excellent adsorption ability. Under the optimal conditions the oxidation peak currents of baicalein were linear with the concentration in 0.48–2.0 μmol L−1 and 4.0–140.0 μmol L−1via differential pulse voltammetry and the limit of detection was calculated as 0.010 μmol L−1. The modified electrode was successfully applied to the detection of baicalein content in drug and human urine samples. Meanwhile, the low cost and facile preparation of oyster mushroom based BPC made it become a potential substrate material for electrode modification.

Nonenzymatic electrochemical assay for hydrogen peroxide detection based on green synthesized MnO2 nanosheets

In this study, manganese oxide (MnO2) nanosheets were successfully prepared with a green and cost-effective method by using Gum Arabic as they both reduce agent and template in the absence of other additives. The composition, crystalline structure and morphology of the synthesized MnO2 nanosheets were studied using different characterization methods. The TEM and FESEM images show that the prepared MnO2 exhibits wrinkle-like nanolayer morphology. Then, the performance of the synthesized MnO2 was investigated for electrochemical detection of hydrogen peroxide (H2O2). The electrochemical sensing of H2O2 based on MnO2 nanosheets modified carbon ionic liquid electrode (MnO2/CILE) was constructed by a pasting method and its electrocatalytic performance was studied using cyclic voltammetry and amperometry. Compared with the bare CILE, the MnO2/CILE electrode exhibited good electrocatalytic behavior for H2O2 reduction in alkaline solutions. The fabricated nonenzymatic H2O2 sensor also showed a linear relationship over an extensive concentration range of 5.0 μM to 10.0 mM (r2 = 0.998) with a LOD of 1.0 μM and a response time of fewer than 5 s. In addition, the developed electrochemical sensor displayed excellent anti-interfering ability, good recovery and also good reproducibility on the H2O2 detection in urine samples. The simple synthesis of MnO2 nanosheets and good electrocatalytic activity reveal the promising usefulness of the fabricated sensor for detection of H2O2.

A biomass-derived porous carbon-based nanocomposite for voltammetric determination of quercetin.

Porous carbon was prepared from wheat flour by alkali treatment and carbonization. The resulting biomass-derived porous carbon (BPC) was employed to prepare a Pt-Au-BPC nanocomposite by a hydrothermal method. The material was then placed on the surface of a carbon ionic liquid electrode (CILE). The Pt-Au-BPC was characterized by SEM, XPS, and the modified CILE by electrochemical methods. They revealed a porous structure, a large specific surface with high conductivity. Pt-Au-BPC/CILE was applied to the sensitive determination of quercetin. Electrochemical response was studied by cyclic voltammetry and differential pulse voltammetry (DPV). Under optimized experimental conditions, the oxidation peak current (measured at 0.48V vs. Ag/AgCl by DPV) increases linearly in the 0.15 to 6.0μM and in the 10.0 to 25.0μM quercetin concentration range. The detection limit is 50.0nM (at 3σ). The Pt-Au-BPC/CILE was applied to the direct determination of quercetin in ginkgo tablets sample and gave satisfactory results. Graphical abstract APt-Au-BPC nanocomposite modified carbon ionic liquid electrode was applied to differential pulse voltammetric determination of quercetin.BPC:biomass-derived porous carbon.

Myoglobin- and Hydroxyapatite-Doped Carbon Nanofiber-Modified Electrodes for Electrochemistry and Electrocatalysis.

In this paper, a hydroxyapatite (HAp)-doped carbon nanofiber (CNF)-modified carbon ionic liquid electrode (CILE) was prepared and used for the investigation on the direct electrochemistry and electrocatalysis of myoglobin (Mb). HAp nanoparticles were mixed within a polyacrylonitrile (PAN) solution, and a HAp@PAN nanofiber was synthesized by electrospinning process, which was further controlled by carbonization at 800 °C for 2 h in a nitrogen atmosphere to get a HAp@CNF nanocomposite. Various techniques were used to check the physicochemical properties of HAp@CNF. Mb was mixed with a HAp@CNF dispersion solution and casted on the surface of CILE to obtain an electrochemical sensing platform. The direct electrochemistry of Mb on the modified electrode was checked when a pair of enhanced redox waves appeared, indicating the direct electron transfer of Mb. HAp@CNF exhibited high conductivity, good biocompatibility, and large surface area, which was beneficial for Mb immobilization. The modified electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid and sodium nitrite, which was further used to establish a new electroanalytical method. Real samples were analyzed by the proposed method with satisfactory results.

A sensitive electrochemical sensor for detection of rutin based on a gold nanocage‐modified electrode

In this article, an electrochemical sensor based on a gold nanocage (AuNC)‐modified carbon ionic liquid electrode (CILE) was fabricated and applied to the sensitive rutin determination. The presence of AuNCs on the electrode surface greatly improved the electrochemical performance of the working electrode due to its specific microstructure and high metal conductivity. Electrochemical behavior of rutin on AuNCs/CILE was studied using cyclic voltammetry and differential pulse voltammetry with the related electrochemical parameters calculated. Under the optimal experimental conditions, the oxidation peak current of rutin and its concentration had good linear relationship in the range from 4.0 × 10−9 to 7.0 × 10−4 mol/L with a low detection limit of 1.33 × 10−9 mol/L (3σ). This fabricated AuNCs/CILE was applied to direct detection of the rutin concentration in drug samples with satisfactory results, showing the real application of AuNCs in the field of chemically modified electrodes.

CuO/Cu2O nanoparticles: A simple and green synthesis, characterization and their electrocatalytic performance toward formaldehyde oxidation

A simple, low cost, stable and sensitive electrochemical sensor based on copper oxide nanoparticles (CuO/Cu2O NPs) was developed for oxidation of formaldehyde. CuO/Cu2O NPs were synthesized with a green and low cost method in the presence of Gum Arabic. During the synthesis process, Gum Arabic acted as a stabilizing agent. The morphology, crystal structure and chemical composition of as-prepared CuO/Cu2O nanostructure were performed through field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction techniques. The CuO/Cu2O NPs modified carbon ionic liquid electrode (CuO/Cu2O/CILE) was designed and its catalytic activity was investigated toward formaldehyde oxidation. Compared with bare carbon ionic liquid electrode, the modified electrode exhibited efficient catalysis to direct formaldehyde oxidation. The obtained results show CuO/Cu2O/CILE electrode indicates good electrocatalytic activity toward formaldehyde oxidation with a linear range from 0.1 mmolL−1–110 mmolL−1 and a limit of detection of 10 μmolL−1. Moreover, the prepared electrode exhibited good long term stability and good reproducibility. A simple and green route for synthesis of CuO/Cu2O NPs together with good electrocatalytic activity toward formaldehyde oxidation show that the CuO/Cu2O/CILE is one of the most promising systems for detection of formaldehyde.

Gold Nanocage-Based Electrochemical Sensing Platform for Sensitive Detection of Luteolin.

A simple and sensitive electrochemical sensor was developed for the detection of tracelevels of luteolin. The sensoris based on a novel type of chemically modified electrode: gold nanocage (AuNCs)-modified carbon ionic liquid electrode (CILE). To construct this electrochemical sensing platform for luteolin, CILE is initially prepared by using 1-hexylpyridinium hexafluorophosphate as the binder and then AuNCs are coated on the surface of CILE to fabricate AuNCs-modified CILE (AuNCs/CILE). Electrochemical studies have shown that AuNCs/CILE can exhibit enhanced electrocatalytic activity toward the redox reaction of luteolin, therefore, the redox peak current of luteolin can be greatly improved, resulting in the high sensitivity of the developed sensor. Under the optimal conditions, the oxidation peak currents of the sensor increase linearly with an increase in the luteolin concentration in a range from 1 to 1000 nM with a detection limit of 0.4 nM, which is lower than those of most reported electrochemical luteolin sensors. Moreover, the reproducibility, precision, selectivity, and stability of this sensor are excellent. Finally, the sensing system was applied to the analysis of luteolin-spiked drug samples and the recovery in all cases was 95.0–96.7%, indicating the potential application of this simple, facile, and sensitive sensing system in pharmaceutical analysis.

A graphene modified carbon ionic liquid electrode for voltammetric analysis of the sequence of the Staphylococcus aureus nuc gene.

The authors describe a voltammetric method for the detection of the nuc ssDNA sequence originating from Staphylococcus aureus by using a carbon ionic liquid electrode modified with electrodeposited three-dimensional graphene (3DGR). Probe ssDNA was electrostatically adsorbed on the modified electrode by a potentiostatic method. The porous structure and large surface area of 3DGR greatly increase the amount of immobilized probe ssDNA on the interface, which is beneficial for the reaction with target ssDNA. By using Methylene Blue (MB) as the electrochemical probe, the reduction peak current of MB (best measured at -0.30V vs. SCE) can be used for detecting hybridization. The differential pulse voltammetric current of MB increases linearly in the 1.0 × 10-12mol L-1 to 1.0 × 10-6mol L-1 nuc concentration range, and the detection limit is 3.3× 10-13mol L-1 (at 3σ). The DNA sensor was successfully applied to the determination of the PCR product of the gene in pork. Graphical abstract Response of an electrochemical DNA biosensor based on the use of a carbon ionic liquid electrode modified with three-dimensional graphene. It enables sensitive voltammetric detection of the specific sequence of the Staphylococcus aureus nuc gene.

A yolk shell Fe3O4 @PA-Ni@Pd/Chitosan nanocomposite -modified carbon ionic liquid electrode as a new sensor for the sensitive determination of fluconazole in pharmaceutical preparations and biological fluids

In this study, a versatile method was used to synthesize Ni@Pd core–shell nanoparticles, immobilized on Fe3O4@polyaniline yolk–shell composites (Fe3O4@PA). The constructed Fe3O4@PA-Ni@Pd composite and Chitosan were utilized for the modification of carbon ionic liquid electrode (CILE) in high sensitive determination of fluconazole (FLU). A carbon ionic liquid electrode constructed using graphite powder mixed with 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) in place of paraffin as the binder showed strong electrocatalytic activity to the direct oxidation of Fluconazole. The properties of the electrode surface were characterized by scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA), X-Ray Photo-Emission Electron Microscopy (XPES), Electrochemical Impedance Spectroscopy (EIS), Chronocoulometry (CC) and chronoamperometery (CA) techniques. The recommended quadratic model obtained from the full factorial Box–Behnken design (BBD) was in accordance with the experimental data in an acceptable range. The response was studied in relation to such critical factors as pH, accumulation time, concentration of nanoparticles, and scan rate. The peak currents were proportional to fluconazole concentration in a linear range from 0.01 to 400μmolL−1, with a detection limit of 3.5nmolL−1. Then the constructed sensor was successfully used for the quantification of fluconazole in serum, urine, and tablets.

Investigation on direct electrochemical and electrocatalytic behavior of hemoglobin on palladium-graphene modified electrode

Palladium-graphene (Pd-GR) nanocomposite was acted as modifier for construction of the modified electrode with direct electrochemistry of hemoglobin (Hb) realized. By using Nafion as the immobilization film, Hb was fixed tightly on Pd-GR nanocomposite modified carbon ionic liquid electrode. Electrochemical behaviors of Hb modified electrode were checked by cyclic voltammetry and a pair of redox peaks originated from direct electron transfer of Hb was appeared. The Hb modified electrode had excellent electrocatalytic activity to the reduction of trichloroacetic acid and sodium nitrite in the concentration range from 0.6 to 13.0mmol·L−1 and from 0.04 to 0.5 mmol·L−1. Therefore Pd-GR nanocomposite was proven to be a good candidate for the fabrication of third-generation electrochemical biosensor.

Electrocatalytic oxidation and determination of dexamethasone at an Fe3O4/PANI–CuII microsphere modified carbon ionic liquid electrode

A novel, simple, sensitive and selective electrochemical sensor based on an Fe3O4/PANI–CuII microsphere modified carbon ionic liquid electrode is constructed and utilized for the determination of dexamethasone.

Facile synthesis of Pt-Cu@silicon nanostructure as a new electrocatalyst supported matrix, electrochemical detection of hydrazine and hydrogen peroxide

In this work, a facile approach is presented to synthesis Pt-Cu nanoalloy with time scale of a few minutes at room temperature. Pt-Cu nanoalloy was supported on the surface of porous silicon (PSi) powder by a simple in-situ redox reaction between PtCl62−/Cu2+ and PSi, in hydrofluoric acid solution. The morphological, chemical and electrochemical properties of the prepared nanostructure were characterized using field emission scanning electron microscopy, X-ray diffraction spectroscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and chronoamperometry. Then, the electrocatalytic activity of Pt-Cu@PSi toward hydrazine oxidation and hydrogen peroxide reduction was investigated and were compared with Pt@PSi and Cu@PSi. The results showed that Pt-Cu@PSi has higher electrocatalytic for both the analytes. To have better behavior of the electrocatalyst for the detection of hydrazine and hydrogen peroxide, Pt-Cu@PSi modified carbon ionic liquid electrode (CILE) was fabricated. Using the proposed electrochemical sensor, hydrogen peroxide could be measured in the range of 0.5–1280μmolL−1 with detection limit of 100nmolL−1, whereas hydrazine could be measured in the range of 0.20–1680μmolL−1 with detection limit of 50 nmol L−1, using chronoamperometry technique. Finally, the prepared electrochemical sensor was employed to determine hydrogen peroxide and hydrazine in real samples with satisfactory results.