Jagged-shape chaotic attractors of a megastable oscillator with spatially square-wave damping

Background:: new and selective electrochemical sensor was developed for the determination of levocetirizine dihydrochloride, which is an antihistaminic drug. Method:: The investigation was performed by using cyclic, differential pulse and square wave voltammetric methods on the β-cyclodextrin modified glassy carbon electrode. It is thereby planned to obtain information about levocetirizine determination and its mechanism. Result:: The efficiency of experimental parameters including pH, scan rate, and accumulation potential and time on the anodic response of levocetirizine dihydrochloride was studied. By employing the developed method and under optimized conditions, the current showed linear dependence with a concentration in the range between 2 × 10-8 M and 6 × 10-6 M in pH 2.0 Britton Robinson (BR) buffer. Conclusion:: The achieved limits of detection and quantification were found as 3.73 × 10-10 M and 1.24 × 10-9 M, respectively. In addition, the possibility of applying the developed sensor for real sample analysis was investigated, so β-cyclodextrin modified glassy carbon electrode was used to determine levocetirizine dihydrochloride in Xyzal® tablet dosage form. Finally, this sensor was successfully applied to the real sample as a selective, simple, reproducible, repeatable electrochemical sensor.

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Facile and Fast Detection of Genistein in Derris scandens by Square Wave Voltammetry using a Cobalt(II) Phthalocyanine-Modified Screen-Printed Electrochemical Sensor

Current Analytical Chemistry ◽

10.2174/1573411014666180521091053 ◽

2020 ◽

Vol 16 (3) ◽

pp. 341-348

Author(s):

Surinya Traipop ◽

Suchada Chuanuwatanakul ◽

Orawon Chailapakul ◽

Eakkasit Punrat

Keyword(s):

Electrochemical Sensor ◽

Square Wave Voltammetry ◽

Silver Chloride ◽

Reference Electrode ◽

High Sensitivity ◽

Plastic Substrate ◽

Fast Analysis ◽

Square Wave ◽

Wave Voltammetry ◽

Screen Printed

Background: Recently, Derris scandens, a Thai herbal medicine with anti-inflammatory activity, is widely used as beverage and supplementary food. When the traditional medicine is a choice for health therapy, the simple and reliable equipment is required to control the suitable consuming amount of the active component. Objective: To develop the electrochemical sensor for genistein determination in Derris scandens with high sensitivity and rapid operation. Methods: An in-house screen-printed electrochemical sensor consisting of a three-electrode system was developed for genistein determination. A silver/silver chloride (Ag/AgCl) reference electrode, a carbon counter electrode and a carbon working electrode were prepared on a 0.3-mm-thick plastic substrate by the screen-printing technique using conductive ink. The dimensions of each sensor were 2.5×1.0 cm. Only 50 µL of sample solution was required on this device for the determination of genistein concentration by rapid response square wave voltammetry. Results: The oxidation peak of genistein appeared with good response in acidic media at a peak potential of 0.6 V. Moreover, the signal was enhanced by modifying the conductive carbon ink with cobalt( II) phthalocyanine. Under the optimized conditions, the linear range was found to be 2.5-150 µM and the detection limit was 1.5 µM. Moreover, the small volume extraction was successfully developed without any further pre-concentration. This proposed method was applied to determine genistein in Derris scandens with satisfying results. Conclusion: The proposed method is promising as an alternative method for genistein determination with facile and fast analysis.

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Simultaneous Monitoring of Febuxostat and Uric Acid in Human Serum Samples Using the Direct Square-Wave Voltammetric Method

Current Analytical Chemistry ◽

10.2174/1573411014666180730112905 ◽

2019 ◽

Vol 15 (6) ◽

pp. 678-684

Author(s):

Biljana Nigović ◽

Jakov Vlak

Keyword(s):

Uric Acid ◽

Human Serum ◽

Oxidase Inhibitor ◽

Serum Samples ◽

Boron Doped Diamond ◽

Fast Analysis ◽

Xanthine Oxidase Inhibitor ◽

Voltammetric Method ◽

Square Wave ◽

Human Serum Samples

Background: High uric acid serum level, hyperuricemia, is now associated with many diseases such as gout, chronic kidney disease, hypertension, coronary artery disease and diabetes. Febuxostat is a novel selective xanthine oxidase inhibitor approved for the treatment of hyperuricemia. Objective: The aim of this study was to develop a first analytical method for the simultaneous determination of febuxostat and uric acid. Methods: An unmodified boron-doped diamond electrode provided concurrent quantitation of drug at low levels and uric acid, which has clinical significance in the diagnosis and therapy of hyperuricemia, at relatively high concentrations. The direct square-wave voltammetric method was applied to the analysis of both analytes in human serum samples. Results: Under the optimized conditions, the linear response of peak current on febuxostat concentration was achieved in the range from 7.5 × 10-7 to 3 × 10-5 M, while uric acid showed two linear ranges of 5 × 10-6 - 5 × 10-5 M and 5 × 10-5 - 2 × 10-4 M. The method was successfully utilised for quantification of both analytes in human serum samples. Good recoveries were obtained without interference from common inorganic cations and anions as well as glucose, dopamine, ascorbic and folic acids at concentrations expected in physiological conditions. Conclusion: The great benefits of developed method are fast analysis (only 7.5 s for run), low cost and simplicity of performance.

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Tollmien--Schlichting wave damping by a streamwise oscillating Lorentz force

Magnetohydrodynamics ◽

10.22364/mhd.44.3.1 ◽

2008 ◽

Vol 44 (3) ◽

pp. 205-222 ◽

Cited By ~ 7

Author(s):

T. Albrecht ◽

H. Metzkes ◽

R. Grundmann ◽

G. Mutschke ◽

G. Gerbeth

Keyword(s):

Lorentz Force ◽

Wave Damping ◽

Tollmien Schlichting

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Development of a Microcontroller-Based 6/12/18/24V Power Inverter Circuit

Journal of Communications Technology Electronics and Computer Science ◽

10.22385/jctecs.v10i0.144 ◽

2017 ◽

Vol 10 ◽

pp. 19

Author(s):

Abiodun Ogunseye ◽

Daniel Ogheneovo Johnson

Keyword(s):

Tolerance Limits ◽

C Language ◽

Dc Voltage ◽

Square Wave ◽

Design Specifications ◽

Development Tool ◽

Nominal Voltage ◽

Single Input ◽

Inverter Circuit

A power inverter circuits is normally designed to meet its design specifications when the applied input DC voltage is within specified tolerance limits. Thus, single input inverters are usually specified to work from a DC source having a fixed nominal voltage. This limits the usefulness of the inverter circuit when a DC source having the specified nominal voltage is not available. In this work, a modified square wave inverter system that is specified to work properly from batteries with nominal voltages of 6, 12, 18 and 24 V was designed. A model of the microcontroller-based circuit was developed with Proteus® software and its firmware was written in C language using the MicroC® development tool. A prototype of the circuit was constructed and then tested. The constructed circuit was found to work properly by producing a 50 Hz modified square waveform when it was powered from batteries having nominal voltages of 6 V, 12 V, 18 V and 24 V.

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Isopotential points in square-wave voltammetry of reversible electrode reactions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2009068 ◽

2009 ◽

Vol 74 (10) ◽

pp. 1489-1501 ◽

Cited By ~ 3

Author(s):

Marina Zelić ◽

Milivoj Lovrić

Keyword(s):

Square Wave Voltammetry ◽

Electrode Reaction ◽

Time Model ◽

Model Calculations ◽

Square Wave ◽

Electrode Reactions ◽

Wave Voltammetry ◽

Electron Transfer Processes ◽

Diagnostic Criterion ◽

First Time

Isopotential points in square-wave voltammetry are described for the first time. Model calculations and real measurements (performed with UO22+ and Eu3+ in perchlorate and bromide solutions, respectively) indicate that such an intersection could be observed when backward components of the net response, resulting from an increase in frequency or reactant concentration, are presented together. The electrode reaction should be fully reversible because quasireversible or slower electron transfer processes give the isopoints only at increasing reactant concentrations but not at increasing square-wave frequencies. The effect could be used as an additional diagnostic criterion for recognition of reversible electrode reactions where products remain dissolved in the electrolyte solution.

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