scholarly journals Electrochemical Sensing of Ascorbic Acid, Hydrogen Peroxide and Glucose by Bimetallic (Fe, Ni)−CNTs Composite Modified Electrode

2019 ◽  
Vol 31 (5) ◽  
pp. 851-857 ◽  
Author(s):  
Sayed Tayyab Raza Naqvi ◽  
Bahareh Shirinfar ◽  
Dilshad Hussain ◽  
Saadat Majeed ◽  
Muhammad Naeem Ashiq ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Electrochemical Sensing

scholarly journals ITO ELECTRODES MODIFIED WITH MnO2/SiO2 FOR THE DETERMINATION OF HYDROGEN PEROXIDE

2018 ◽  
pp. 39-42
Author(s):  
A. Kovalyk ◽  
O. Tananaiko
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Detection Limit ◽  
Manganese Dioxide ◽  
Modified Electrode ◽  
Electrode Surface ◽  
Electrochemical Characteristics ◽  
Ito Electrode ◽  
Mno2 Nanoparticles ◽  
H2o2 Determination

Nanostructured transition metal oxide nanoparticles possess a catalytic activity to hydrogen peroxide. Manganese dioxide particles are one of the promising and available modificators of the electrode surface. Nanostructured MnO2 deposited onto the surface of the electrode enhances the electron transport from the H2O2 molecule to the surface. Thus selectivity and sensitivity of H2O2 detection can be improved. There are a lot of different methods of the impregnation of manganese dioxide particles onto electrode surface. An electrophoretic deposition is one of the most simple and rapid. By adjusting the electrodeposition parameters, particles of different sizes or films can be obtained. A simple and novel hydrogen peroxide sensor based on layer-by-layer assembly of MnO2 nanoparticles and SiO2 film on the ITO electrode was developed. For this purpose MnO2 nanoparticles were electrodeposited on the surface of ITO electrode from MnSO4/CH3COOK solution. The electrochemical characteristics of the modified electrodes were investigated by cyclic voltammetry.The presence of MnO2 on the surface of modified electrode was indicated by the appearance of clear oxidation-reduction peaks of Mn(IV)/Mn(III,II) at E=0.65 V in the electrolyte solution in contrast to unmodified electrode. Optimization of measurement parameters such as the amount of MnO2, applied potential and pH value were studied in details. Under the optimum conditions, the calibration curve for H2O2 determination using modified electrode was linear in the range from 1×10−4 to 1×10−3 mol/dm3 with a detection limit of 0.09×10−4 mol/dm3 (S/N = 3). The linear rang for non-modified electrode was from 1×10−3 to 1×10−2 mol/dm3 with a detection limit of 1.8×10−4 mol/dm3 (S/N = 3). The modified ITO electrode was characterized by higher current than non modified ITO as a result of increasing of electroactive surface area and catalytic effect of electrodeposited MnO2.For the stabilization of MnO2 particles and protection of the electrode surface from impurities, the ITO/MnO2 was covered by thin silica film. The selectivity of H2O2 determination at ITO modified with MnO2/SiO2 was better than at ITO especially in the presence of ascorbic acid which is oxidized at the same potential as H2O2. The oxidation current of ascorbic acid was much higher than H2O2 at nonmodified ITO in contrast to ITO modified with MnO2/SiO2. The developed ITO electrode modified with MnO2/SiO2 is a perspective element of amperometric sensor for the detection of hydrogen peroxide.

scholarly journals Tellurium doped zinc imidazole framework (Te@ZIF-8) for quantitative determination of hydrogen peroxide from serum of pancreatic cancer patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Batool Fatima ◽  
Dilshad Hussain ◽  
Adeela Saeed ◽  
Muhammad Salman Sajid ◽  
Saadat Majeed ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Hydrogen Peroxide ◽  
Quantitative Determination ◽  
Cancer Patients ◽  
Modified Electrode ◽  
Electrochemical Sensing ◽  
Serum Samples ◽  
Scanning Calorimetry ◽  
X Ray

AbstractThe tellurium doped zinc imidazole framework (Te@ZIF-8) is prepared by a two-step hydrothermal strategy for the electrochemical sensing of hydrogen peroxide. Material is characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The electrochemical characterization of the MOF modified electrode is done by a three-electrode system. Electrochemical sensing of hydrogen peroxide is made by cyclic voltammetry, amperometry, and impedance measurements. Results demonstrate that Te@ZIF-8 shows a detection limit of 60 µM with linearity up to 0.98855. Material is stable to 1000 cycles with no significant change in electrochemical response. Amperometry depicts the recovery of hydrogen peroxide from human serum up to 101%. Impedance curve reveals the surface of Te@ZIF-8-GCE (glassy carbon electrode) as porous and rough and an interface is developed between analyte ions and the sensing material. Finally, the modified electrode is used for the quantitative determination of hydrogen peroxide from serum samples of pancreatic cancer patients, diagnosed with CA 19-9.

scholarly journals Highly Selective and Reproducible Electrochemical Sensing of Ascorbic Acid Through a Conductive Polymer Coated Electrode

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1346 ◽  
Author(s):  
Salma Bilal ◽  
Ayesha Akbar ◽  
Anwar-ul-Haq Ali Shah
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Voltammetry ◽  
Modified Electrode ◽  
Limit Of Detection ◽  
Conductive Polymer ◽  
Micelle Formation ◽  
Electrochemical Sensing ◽  
A Value ◽  
One Step ◽  
Doped Polyaniline

The surface of an Au-disc electrode was modified through electro polymerization of aniline, in the presence of dodecyl benzene sulphonic acid (DBSA) and sulphuric acid (H2SO4) solution. The polymerization conditions were pre-optimized so that micelle formation and solution coagulation could be minimized and surfactant doped polyaniline film could be obtained through a quick, simple and one step polymerization route. The synthesized material was characterized via Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The effective surface area of the Au-disc, calculated through cyclic voltammetry, was immensely increased through a polyaniline (PANI) coating (0.04 and 0.11 cm2 for bare and PANI coated gold respectively). The modified electrode was utilized for ascorbic acid (AA) sensing. The changing pH of electrolyte and scan rate influenced the PANI electrode response towards AA. The modified electrode was highly selective towards AA oxidation and showed a very low limit of detection i.e. 0.0267 μmol·L–1. Moreover, the PANI coating greatly reduced the sensing potential for AA by a value of around 140 mV when compared to that on a bare gold electrode.

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals Paper-Based Competitive Immunochromatography Coupled with an Enzyme-Modified Electrode to Enable the Wireless Monitoring and Electrochemical Sensing of Cotinine in Urine

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1659
Author(s):  
Nutcha Larpant ◽  
Pramod K. Kalambate ◽  
Tautgirdas Ruzgas ◽  
Wanida Laiwattanapaisal
Keyword(s):  
Glucose Oxidase ◽  
Modified Electrode ◽  
Near Field ◽  
Electrochemical Measurement ◽  
Electrochemical Sensing ◽  
Urine Samples ◽  
Lateral Flow Strip ◽  
Wireless Monitoring ◽  
Sensing Platform ◽  
Combined Strategy

This paper proposes a combined strategy of using paper-based competitive immunochromatography and a near field communication (NFC) tag for wireless cotinine determination. The glucose oxidase labeled cotinine antibody specifically binds free cotinine in a sample, whereas the unoccupied antibody attached to BSA-cotinine at the test line on a lateral flow strip. The glucose oxidase on the strip and an assistant pad in the presence of glucose generated H2O2 and imposed the Ag oxidation on the modified electrode. This enabled monitoring of immunoreaction by either electrochemical measurement or wireless detection. Wireless sensing was realized for cotinine in the range of 100–1000 ng/mL (R2 = 0.96) in PBS medium. Undiluted urine samples from non-smokers exhibited an Ag-oxidation rate three times higher than the smoker’s urine samples. For 1:8 diluted urine samples (smokers), the proposed paper-based competitive immunochromatography coupled with an enzyme-modified electrode differentiated positive and negative samples and exhibited cotinine discrimination at levels higher than 12 ng/mL. This novel sensing platform can potentially be combined with a smartphone as a reader unit.

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