scholarly journals Synthesis of Polypyrrole Inverse Opal in [bmim]PF6-Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Yan ◽  
Qi-Qi Dong ◽  
Li-Ning Sun ◽  
Wei Deng ◽  
Shaoping Wu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Phosphate Buffer Solution ◽  
Open Circuit ◽  
Acetonitrile Solution ◽  
Cyclic Voltammograms ◽  
Inverse Opal ◽  
Buffer Solution ◽  
Metallic Oxide ◽  
Experimental Conditions ◽  
Inverse Opals

Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered polypyrrole (PPy) inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF6. PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS) were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that thePF6-anions kept dedoping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. AlthoughPF6-anions also kept dedoping from the PPy inverse opals, thePO43-anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours.

scholarly journals Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 235
Author(s):  
Mohammed M. Rahman ◽  
Jahir Ahmed ◽  
Abdullah M. Asiri ◽  
Sulaiman Y.M. Alfaifi ◽  
Hadi. M. Marwani
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Dynamic Range ◽  
Sol Gel ◽  
Phosphate Buffer Solution ◽  
Fast Response ◽  
Buffer Solution ◽  
Metallic Oxide ◽  
X Ray ◽  
Methanol Sensor

Herein, novel Co3O4·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles’ structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/μ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/μ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/μ-Chip sensor, such as excellent sensitivity (1.3842 µAµM−1cm−2), a wide linear dynamic range of 1.0 nM–2.0 mM (R2 = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/μ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

Drug-loaded ultrafine poly(vinyl alcohol) fibre mats prepared by electrospinning

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Chunxue Zhang ◽  
Xiaoyan Yuan ◽  
Lili Wu ◽  
Jing Sheng
Keyword(s):  
Drug Release ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Phosphate Buffer Solution ◽  
Poly Vinyl Alcohol ◽  
High Porosity ◽  
Buffer Solution ◽  
Drug Molecules ◽  
Alcohol Fibre

AbstractSubmicron poly(vinyl alcohol) (PVA) fibre mats embedded with Aspirin and bovine serum albumin (BSA) were prepared by electrospinning of their aqueous solutions. Fibre morphology was investigated by scanning electron microscopy. The composition of the fibre mats was characterized by Fourier transform IR spectroscopy and X-ray photoelectron spectroscopy. The in vitro drug release was investigated by immersing the fibre mats in phosphate buffer solution at 37°C. Results indicated that the morphology of fibre mats was influenced by the amount of drug, and more beaded and irregularly shaped fibres were found with increasing drug amounts. There were drug molecules distributed on the surface of the PVA fibres. Studies of in vitro drug release showed that both Aspirin and BSA were released more quickly from PVA fibre mats than from PVA films because of the large surface area and high porosity of the fibre mats.

Three-Dimensional Glucose/Oxygen Biofuel Cells Based on Enzymes Embedded in Tetrabutylammonium Modified Nafion

2021 ◽  
Vol 18 (4) ◽  
Author(s):  
Yuchen Hui ◽  
Xiaoyan Ma ◽  
Rong Cai ◽  
Shelley D. Minteer
Keyword(s):  
Direct Electron Transfer ◽  
Glucose Dehydrogenase ◽  
Tetrabutylammonium Bromide ◽  
Three Dimensional ◽  
Phosphate Buffer Solution ◽  
Open Circuit ◽  
Biofuel Cell ◽  
Buffer Solution ◽  
Multi Wall Carbon Nanotubes ◽  
Enzymatic Biofuel Cell

Abstract A stable three-dimensional glucose/oxygen enzymatic biofuel cell is fabricated based on the method of polymer encapsulation-based immobilization. And three-dimensional carbon felt is used as the substrate of the bio-electrode for increasing enzymatic loading density. Gold nanoparticles and multi-wall carbon nanotubes are employed to promote direct electron transfer and enhance conductivity and electron conduction rate of bio-electrodes. Glucose dehydrogenase and bilirubin oxidase are immobilized with tetrabutylammonium bromide (TBAB) modified Nafion, which enhances the stability of the bio-electrodes by the immobilization method. A membrane-free glucose/oxygen biofuel cell is assembled with a high open-circuit voltage of 0.85 V and a maximum power density of 21.9 ± 0.1 μW/cm2 in 0.1 M pH 7.0 phosphate buffer solution with 100 mM glucose and air saturation. And the biofuel cell shows high stability to the condition. After 60 days of periodic storage experiments, the performance of the enzymatic biofuel cell still maintained 90.3% of its electrochemical performance.

Cyclic voltammetry of natural flavonoids on MWNT-modified electrode and their determination in pharmaceuticals

2011 ◽  
Vol 76 (12) ◽  
pp. 1619-1631 ◽  
Author(s):  
Guzel Ziyatdinova ◽  
Ilmira Aytuganova ◽  
Alfiya Nizamova ◽  
Mikhail Morozov ◽  
Herman Budnikov
Keyword(s):  
Cyclic Voltammetry ◽  
Dynamic Range ◽  
Phosphate Buffer Solution ◽  
Cyclic Voltammograms ◽  
Buffer Solution ◽  
Coulometric Determination ◽  
Average Roughness ◽  
Pharmaceutical Dosage Forms ◽  
Force Microscopy ◽  
Relative Standard

The determination of rutin, quercetin and taxifolin in pharmaceutical dosage forms using cyclic voltammetry on multi-walled carbon nanotube modified glassy carbon electrode (MWNT-GCE) has been developed. The surface of the electrode created has been characterized by atomic force microscopy. Electrode modification with MWNT increases the surface average roughness (190-fold) and structures it. There are two oxidation steps at 0.22 and 0.80, 0.23 and 0.80, 0.26 and 0.86 V on cyclic voltammograms of taxifolin, quercetin and rutin, respectively, in phosphate buffer solution of pH 7.4. The linear dynamic range is 1.4–28 and 28–210, 2.0–220 and 0.52–210 μM with detection limits of 0.71, 1.0 and 0.26 μM for rutin, quercetin and taxifolin, respectively. The relative standard deviation of flavonoids determination in pharmaceuticals does not exceed of 7%. The data obtained are in good agreement with coulometric determination.

Chiral Separation of Racemic Naproxen by High-Performance Liquid Chromatography with β-CD/SiO2 as the Chiral Stationary Phase

2014 ◽  
Vol 97 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Lili Wang ◽  
Jian Deng ◽  
Xuezhen Ji ◽  
Wanbin Liu ◽  
Jun Liang ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Chiral Separation ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Chiral Stationary Phase ◽  
Separation Efficiency ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Scanning Calorimetry ◽  
Column Temperature

Abstract A novel derivative β-cyclodextrin (β-CD) bonded silica gel (β-CD/SiO2) was prepared via carbodiimide activation and used as a chiral stationary phase (CSP). The β-CD/SiO2 CSP was characterizedby X-ray photoelectron spectroscopy and FTIR spectroscopy to prove the successful immobilization of β-CD onto the surface of the silica gel.The thermal behavior of the CSP was studied by differential scanning calorimetry and then used forthe chiral separation of racemic naproxen using HPLC. Several factors affecting the separation efficiency of naproxen enantiomers were investigatedsystematically. The following parameters were selected: methanol–0.01 M phosphate buffer solution (85 + 15, v/v, pH 3.5) was the mobile phase, the flow rate was 1.0 mL/min, and the column temperature was 35°C. Under optimal conditions, the racemic naproxen was efficiently separated with a resolution factor (RS) of 1.70 and a separation factor (α) of 1.25. This method was successfully used for the enantiomeric separation and purity assessment of naproxen in commercial naproxen sustained release tablets.

Photoelectrochemical Sensing of Hydrazine Based on Palladium Film Modifying N-Silicon Electrode under Visible Irradiation

2014 ◽  
Vol 1006-1007 ◽  
pp. 811-814
Author(s):  
Huai Xiang Li ◽  
Jin Chao Hu ◽  
Qiong Wu ◽  
Wen Hua Song
Keyword(s):  
Cyclic Voltammetry ◽  
Electron Microscope ◽  
Modified Electrode ◽  
Photoelectron Spectroscopy ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
X Ray ◽  
Visible Irradiation ◽  
Photo Electrode ◽  
Scanning Electron

In this work, a palladium film has been evaporated on an n-silicon (n-n+-Si) surface and electrochemically activated by cyclic voltammetry (CV) to form a modified silicon photo-electrode. Scanning electron microscope (SEM) and x-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and composition of the modified electrode surface. A new photoelectrochemical (PEC) cell based on the modified electrode was used as sensor for hydrazine determination by photocurrent measurements. The sensor showed good photocurrent responses by adding different concentrations of hydrazine with a good stability. The linear ranges for the detection of hydrazine are 2 to 20 μM with a detection limit of 0.5 μM in pH=7.0 phosphate buffer solution (PBS).

scholarly journals A facile synthesis of GO/CuO-blended nanofiber sensor electrode for efficient enzyme-free amperometric determination of glucose

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Medha Gijare ◽  
Sharmila Chaudhari ◽  
Satish Ekar ◽  
Anil Garje
Keyword(s):  
Photoelectron Spectroscopy ◽  
Research Work ◽  
Phosphate Buffer Solution ◽  
Linear Sweep Voltammetry ◽  
Morphological Properties ◽  
Buffer Solution ◽  
Amperometric Determination ◽  
Detection Range ◽  
X Ray ◽  
Sensing Performance

AbstractThe development of biosensors with innovative nanomaterials is crucial to enhance the sensing performance of as-prepared biosensors. In the present research work, we prepared copper (II) oxide (CuO) and graphene oxide (GO) composite nanofibers using the hydrothermal synthesis route. The structural and morphological properties of as-prepared GO/CuO nanofibers were analyzed using an X-ray diffractometer, field-emission scanning, energy dispersive X-ray analysis, Fourier transmission infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The results indicated GO/CuO nanofibers exhibit nanosized diameters and lengths in the order of micrometers. These GO/CuO nanofibers were employed to prepare non-enzymatic biosensors (GO/CuO nanofibers/FTO (fluorine-doped tin oxide)) modified electrodes for enhanced glucose detection. The sensing performance of the biosensors was evaluated using linear sweep voltammetry (LSV) and chronoamperometry in phosphate buffer solution (PBS). GO/CuO/FTO biosensor achieved high sensitivity of 1274.8 μA mM−1cm−2 having a linear detection range from 0.1 to 10 mM with the lower detection limit (0.13 μM). Further, the prepared biosensor showed good reproducibility repeatability, excellent selectivity, and long-time stability. Moreover, the technique used for the preparation of the GO/CuO composite is simple, rapid, cost-effective, and eco-friendly. These electrodes are employed for the detection of glucose in blood serum with RSD ~ 1.58%.

A comparison of corrosion behaviors of additive manufacturing cobalt-chromium alloy in different solutions

2019 ◽  
Vol 116 (3) ◽  
pp. 311
Author(s):  
Liyan Ma ◽  
Jia Niu
Keyword(s):  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Phosphate Buffer Solution ◽  
Open Circuit ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Buffer Solution ◽  
Cocr Alloy ◽  
Superior Corrosion Resistance

The corrosion behavior of selective laser melted CoCr alloy in 0.9% NaCl, phosphate buffer solution (PBS) and artificial saliva (AS) solutions were studied by using open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. The potentiodynamic polarization tests were shown the lowest current density of the CoCr alloy in 0.9% NaCl, while the highest one was measured in PBS solution. CoCr alloys were passivation in all solutions, and the protective scale formed on CoCr alloy in 0.9% NaCl solution possessed the superior corrosion resistance according to EIS results.

Sensitive Detection of Human Hemoglobin by MWCNTs-ionic Liquid: Anthraquinone Modified Electrode

2019 ◽  
Vol 9 (4) ◽  
pp. 479-485
Author(s):  
Aghdas Banaei ◽  
Mostafa Shourian ◽  
Fariba Dashtestani ◽  
Khadijeh Eskandari
Keyword(s):  
Ionic Liquid ◽  
Modified Electrode ◽  
Clinical Sample ◽  
Phosphate Buffer Solution ◽  
Cyclic Voltammograms ◽  
Buffer Solution ◽  
Solution Ph ◽  
Nano Composite ◽  
Composite Gels ◽  
Composite Gel

Introduction: Today, nano-composite gels based on multi-walled carbon nanotubes in room temperature ionic liquid (MWCNTs-IL-Gel) are an interesting subject. Materials and Methods: The nano-composite gels showed convenient electrochemical properties against redox activities of electroactive biomolecules. Also, the evaluation of hemoglobin concentration is a critical point in the clinical sample. So, the kind of nano-composite gel which is composed of NH2 functionalized MWCNTs and [amim] Br IL and anthraquinone 2-carboxilic acid (AQ) was fabricated and applied in electrochemical detection of hemoglobin. Cyclic voltammograms of NH2.MWCNTs-IL-AQ modified electrode exhibited redox peak sat -0.5 V (vs. Ag/AgCl) in 0.1 M phosphate buffer solution ((pH 7.0). Results: As the hemoglobin added into the measured solution, the redox current decreased. Conclusion: It can be concluded that the increment in the concentration of hemoglobin caused the decrease in the redox currents in cyclic voltammetry. The NH2.MWCNTs-IL-AQ would detect the concentration of hemoglobin from 1.64 x10−8 to 4.89x10−7 M.

scholarly journals Voltammetric quantification of a nonsteroidal anti-inflammatory agent diflunisal based on the enhancement effect of cationic surfactant on boron-doped diamond electrode

2021 ◽  
Vol 40 (1) ◽  
pp. 11
Author(s):  
Ertuğrul Keskin ◽  
Shabnam Allahverdiyeva ◽  
Amer Alali ◽  
Yavuz Yardım
Keyword(s):  
Cationic Surfactant ◽  
Supporting Electrolyte ◽  
Phosphate Buffer Solution ◽  
Open Circuit ◽  
Enhancement Effect ◽  
Boron Doped Diamond ◽  
Buffer Solution ◽  
Solution Ph ◽  
Square Wave ◽  
Boron Doped

The present work describes a simple, fast, and inexpensive voltammetric method for diflunisal measurement using a non-modified boron-doped diamond (BDD) electrode. The oxidation of the agent was irreversible and presented a diffusion‐controlled process. The sensitivity of the square wave voltammetric measurements were significantly improved when the cationic surfactant, cetyltrimethylammonium bromide (CTAB), was present in the supporting electrolyte solution. Using square-wave mode, a linear response was obtained for diflunisal quantification in 0.1 mol L-1 phosphate buffer solution (pH 2.5) solution containing 5×10-5 mol L-1 CTAB at +1.07 V (vs. Ag/AgCl) (after 30 s accumulation under open-circuit conditions). Linearity was found for 0.05 to 2.0 μg mL-1 (2.0×10-7-8.0×10-6 mol L-1) with a detection limit 0.013 μg mL-1 (5.2×10-8 mol L-1). The developed approach could be used for the quantification of diflunisal in pharmaceutical formulations.

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