scholarly journals Electroorganic synthesis of disulfonamide substituted p-benzoquinone by hydroquinone electrochemical oxidation

2018 ◽  
Vol 9 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Seba Nassif ◽  
Deeb Bakeer ◽  
Rushdi Madwar ◽  
Waleed Khadam ◽  
Abeer Nakhla
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Synthesis ◽  
Phosphate Buffer Solution ◽  
Electrolytic Cell ◽  
Oxidation Potential ◽  
Atom Economy ◽  
Buffer Solution ◽  
Ethanol Mixture ◽  
Ece Mechanism ◽  
Green Conditions

This study illustrates electrochemical behavior of hydroquinone and 4-amino-6-chloro­benzene-1,3-disulfonamide in the phosphate buffer solution evaluated by cyclic voltammetry. It was found that the peak of the hydroquinone oxidation potential in the presence of 4-amino-6-chlorobenzene-1,3-disulfonamide is shifted to more positive values compared to hydroquinone alone.  Based on these results, the electrochemical synthesis of new disulfonamide substituted p-benzoquinone is proposed and carried out via electro­chemical oxidation of hydroquinone in the presence of 4-amino-6-chlorobenzene-1,3-di­sulfonamide in the electrolytic cell. It has been concluded that hydroquinone is converted into disulfonamide substituted p-benzoquinone via an ECE mechanism. The successful electrochemical synthesis was conducted in the water/ethanol mixture under green conditions without any toxic reagents or solvents and with high atom economy.

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.

Electroanalysis of nicotine at an electroreduced carboxylated graphene modified glassy carbon electrode

2015 ◽  
Vol 7 (3) ◽  
pp. 1147-1153 ◽  
Author(s):  
Hualing Xiao ◽  
Lingen Sun ◽  
Hongling Yan ◽  
Wen Wang ◽  
Jiali Liu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Buffer Solution

Nicotine is determined at a glassy carbon electrode modified with partially electroreduced carboxylated graphene by cyclic voltammetry and semi-derivative treatment after enrichment at −1.1 V in 0.1 M pH 7.0 phosphate buffer solution.

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 Polymethionine modified carbon nanotube sensor for sensitive and selective determination of L-tryptophan

2020 ◽  
Vol 10 (4) ◽  
pp. 305-315
Author(s):  
Nambudumada S. Prinith ◽  
Jamballi G. Manjunatha
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Phosphate Buffer Solution ◽  
Calibration Plot ◽  
Linear Segment ◽  
Current Signal ◽  
Buffer Solution ◽  
Detection Range ◽  
Selective Determination

The electrochemically initiated catalytic oxidation of amino acid L-tryptophan (L-TPN) in phosphate buffer solution has been scrutinized using highly conductive polymethionine modified carbon nanotube paste sensor (PMETCNTPS) through cyclic voltammetry (CV) technique. Compared to the bare carbon nanotube paste sensor (BCNTPS), PMETCNTPS exhibited a quantifiable current signal by CV method. PMETCNTPS was found sensitive to L-TPN concentrations within the linear segment of detection range 1.5 - 8.0×10-5 M. By employing the calibration plot, the detection limit was determined as 6.99×10-7 M. In addition, PMETCNTPS was successfully exploited and validated in determining L-TPN in the pharmaceutical supplement.

scholarly journals Lanthanum Ortho-Ferrite (LaFeO3) Nano-Particles Based Electrochemical Sensor for the Detection of Dopamine

2020 ◽  
Vol 10 (5) ◽  
pp. 6182-6188
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Sensor ◽  
Differential Pulse Voltammetry ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Nano Particles ◽  
Ferric Nitrate ◽  
Buffer Solution ◽  
Pulse Voltammetry ◽  
Modified Sensor

The perovskite type lanthanum ortho ferrite nano-particles (LaFeO3) based electrochemical sensor was developed and used to detect dopamine. For this work the lanthanum ortho ferrite nano-particles (LaFeO3) were synthesized by combustion technique using sugar and ethanolamine with lanthanum oxide and ferric nitrate. For the characterization of newly prepared lanthanum ortho ferrite nano-particles, techniques like FESEM, and TEM were used. The crystallite size was found to be 40 to 46 nm with cubic crystal structure. To check the electrochemical properties of a modified sensor electrode (LaFeO3/GP), the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used. During the experiment, the phosphate buffer solution having pH 6.0 was employed, maintaining the scan rate 100mVs-1 and 50mVs-1 for cyclic voltammetry and Differential pulse voltammetry, respectively.

Synthesis and characterisation of a novel bi-nuclear copper2+ complex and its application as electrode-modifying agent for simultaneous voltammetric determination of dopamine and ascorbic acid

2014 ◽  
Vol 68 (2) ◽  
Author(s):  
Diganta Das ◽  
Babita Sarma ◽  
Sangita Haloi
Keyword(s):  
Ascorbic Acid ◽  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Oxidation Potential ◽  
Buffer Solution ◽  
Electrode Potentials ◽  
Electro Oxidation ◽  
Simultaneous Voltammetric Determination ◽  
Complex Ion

AbstractA new binuclear complex of copper2+, [LCu2+(CH3COO)2Cu2+L](CH3COO)2 where L is N,N-bis(phthalimide)ethylenediamine, was synthesised and characterised. The complex ion [LCu2+ (CH3COO)2Cu2+L]2+ was encapsulated into ZSM-5 zeolite and used to modify the surface of the glassy carbon electrode. This modified electrode, in a phosphate buffer solution at pH 7.0, exhibited an oxidation potential for dopamine (DA) and ascorbic acid (AA) at electrode potentials of 0.230 V and −0.090 V vs. Ag/AgCl respectively, a separation of 0.320 V. The electro-oxidation of DA or AA on the modified electrode is independent of each other. No interference was observed from Na+, K+, Cl−, SO42−, Mg2+, Ca2+, Zn2+, Fe2+, and glucose. The detection limits obtained were 2.91 × 10−7 M for DA and 3.5 × 10−7 M for AA.

scholarly journals Praseodymium ferrite nano-particles based modified electrode and its application in determination of dopamine

2020 ◽  
Vol 10 (4) ◽  
pp. 5855-5859
Keyword(s):  
Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Differential Pulse Voltammetry ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Nano Particles ◽  
Ferric Nitrate ◽  
Buffer Solution ◽  
Pulse Voltammetry

The present works report the graphite based electrochemical sensor modified by nano-sized praseodymium ferrite (np-PrFeO3) materials for the detection of dopamine. The combustion technique was used to synthesize these nanomaterials of np-PrFeO3 using praseodymium oxide and ferric nitrate as precursor materials. The nanomaterials were characterized by field emission scanning electron microscopy and transmission electron microscopy techniques. The crystallite sizes of synthesized nanoparticles (nps) were in the range from 40-45 nm with cubic crystal system. Cyclic voltammetry and Differential pulse voltammetry techniques were used to study the electrochemical property and were observed to be superior to earlier reports. The limit of detection of dopamine at PrFeO3/GP electrode was 600 nM with 5 to 200 µM for linearity range. The phosphate buffer solution of pH 6.0 was used for all experimental work with maintaining the scan rate 100mVs-1 and 50mVs-1 for cyclic voltammetry and Differential pulse voltammetry, respectively.

scholarly journals Carbon Screen-Printed Electrode Coated with Poly (Toluidine blue) as an Electrochemical Sensor for the Detection of Tyramine

2020 ◽  
Vol 2 (1) ◽  
pp. 51
Author(s):  
Lakshmi Devi Chakkarapani ◽  
Martin Brandl
Keyword(s):  
Cyclic Voltammetry ◽  
Toluidine Blue ◽  
Electrochemical Polymerization ◽  
Phosphate Buffer Solution ◽  
Oxidation Peak ◽  
Peak Potential ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Scan Rate ◽  
Screen Printed

In the present work the surface modification of a carbon screen-printed electrode by electrochemical polymerization of toluidine blue (TB) for determination of tyramine is described. The electrochemical polymerization of the electrode with TB was done by cyclic voltammetry at a scan rate of 50 mV/s and a potential sweep between ‒0.7 V and 1.0 V in the presence of 0.5 mM TB in an electrolyte solution. At each cycle, the polymer film started to deposit on the carbon screen-printed electrode which was repeated 20 times. For parameter optimization the electrochemical behavior of the modified electrode was analyzed by amperometric methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A phosphate buffer solution (PBS) was used as an electrolyte for all the amperometric experiments. The electrochemically modified poly-TB-coated carbon-screen-printed electrode showed an oxidation peak potential of tyramine at 0.67 V. The unmodified carbon-screen-printed electrode showed the tyramine oxidation peak potential at 0.9 V. Based on the voltammetric results, it was found that the poly-TB-modified carbon-screen-printed electrode showed higher sensitivity (1.78 µA nM−1 cm−2) than a bare carbon-screen-printed electrode toward tyramine detection. Tyramine in 0.1 M PBS (pH 7.4) was analyzed by cyclic voltammetry from the potential of ‒0.7 to 1.0 V at a scan rate of 50 mV/s. The poly-TB-modified carbon-screen-printed electrode exhibited a linear response between catalytic peak current and tyramine concentration from 0.02 µM to 270.5 µM with a lower detection limit of 0.007 µM (S/N = 3).

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

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