scholarly journals Determination of hydroquinone in a square wave voltammetry procedure using a graphite-polyurethane composite electrode

2006 ◽  
Vol 31 (4) ◽  
pp. 59-62 ◽  
Author(s):  
P. Cervini ◽  
E.T.G. Cavalheiro
Keyword(s):  
Confidence Level ◽  
Square Wave Voltammetry ◽  
Composite Electrode ◽  
Limit Of Detection ◽  
Voltammetric Sensor ◽  
Square Wave ◽  
Polyurethane Composite ◽  
Wave Voltammetry

In order to a better characterization of a graphite-polyurethane composite intended to be used as a voltammetric sensor, the performance in a square wave voltammetric procedure was investigated. Using hydroquinone (HQ) as a probe, the electrode showed to be useful in square wave voltammetry with limit of detection of 0.28 µmol L-1, with recoveries between 99.1 and 101.5%. The results of the proposed method agreed with HPLC ones within 95% confidence level.

Determination of Rutin in Green Tea Infusions Using Square-Wave Voltammetry with a Rigid Carbon-Polyurethane Composite Electrode

2006 ◽  
Vol 18 (10) ◽  
pp. 1028-1034 ◽  
Author(s):  
Andréa R. Malagutti ◽  
Vânia G. Zuin ◽  
Éder T. G. Cavalheiro ◽  
Luiz H. Mazo
Keyword(s):  
Green Tea ◽  
Square Wave Voltammetry ◽  
Composite Electrode ◽  
Square Wave ◽  
Polyurethane Composite ◽  
Wave Voltammetry ◽  
Tea Infusions

Simultaneous Determination of Amlodipine and Irbesartan in Their Pharmaceutical Formulations by Square-Wave Voltammetry

2021 ◽  
Vol 24 ◽  
Author(s):  
İsmail Murat Palabıyık ◽  
Aysegul Dogan ◽  
İncilay Süslü
Keyword(s):  
Simultaneous Determination ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Amlodipine Besylate ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Limit Of Quantitation ◽  
Active Substances

Background: Hypertension is one of the most important health problems in the world and irbesartan and amlodipine are used in combination in various dosages for the treatment of high blood pressure. Objective: The aim of this study is to develop a fast, easy, sensitive, accurate, and precise square-wave voltammetry method for simultaneous determination of irbesartan and amlodipine besylate from pharmaceutical formulations at a hanging mercury drop electrode. Methods: In the applied method, since both active substances gave a peak at different potentials, no interference occurred between them. In optimization studies Britton-Robinson buffer of pH 8.0 was chosen, in which the most appropriate peak shape and maximum peak current were observed. At the same time, as a result of instrumental parameter optimization to obtain reproducible results, 6 mV for scan increment, 30 mV for pulse amplitude, and 50 Hz for frequency were found suitable. Results: As a result of the calibration studies of the optimized method, linear working ranges were determined as 1.00-13.08 µg mL-1 for irbesartan and 5.83-16.51 µg mL-1 for amlodipine besylate. Limit of detection and limit of quantitation values were respectively calculated as 0.63 and 1.00 µg mL-1 for irbesartan and 0.50 and 1.98 µg mL-1 for amlodipine besylate. The results of precision values (RSD) ranged from 0.67% to 2.31% for irbesartan and 0.65% to 1.49% for amlodipine besylate. Accuracy values were calculated as -0.15% to 1.63% for irbesartan and -0.07% to 3.78% for amlodipine besylate. The results obtained from the recovery studies ranged from 101.05% to 102.78% and from 98.88% to 102.20% for amlodipine besylate and irbesartan, respectively. Conclusion: After the validation studies of the developed method were carried out, it was successfully applied to pharmaceutical formulations containing these active substances.

scholarly journals The Study of a New Method to Determine Copper Ion by Square-Wave Voltammetry-Extraction Iodometry at the Liquid/Liquid Interfaces

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Changyan Shi ◽  
Shaoai Xie ◽  
Jinping Jia
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Copper Ion ◽  
New Method ◽  
Limiting Current ◽  
Square Wave ◽  
Indirect Determination ◽  
Wave Voltammetry ◽  
Simulated Wastewater

A new method of indirect determination ofCu2+was developed based on square-wave voltammetry by the oxidation of iodide in organic solvent at the liquid/liquid (L/L) interface. The limit of detection for the determination ofCu2+in this method was found to be5×10−4 mol/L, and the concentration ranged up to1×10−2 mol/L gave a linear limiting current versus concentration response. For the same simulated wastewater, this method showed high accuracy compared with the result tested by sodium diethyldithiocarbamate extraction spectrophotometry. This approach could be applied to the indirect determination of the oxidative heavy metals in the industrial wastewater.

Voltammetric Determination of Fluoren-9-ol and 2-Acetamidofluorene Using Carbon Paste Electrodes

2005 ◽  
Vol 70 (3) ◽  
pp. 292-304 ◽  
Author(s):  
Natalija German ◽  
Saulius Armalis ◽  
Jiří Zima ◽  
Jiří Barek
Keyword(s):  
Differential Pulse Voltammetry ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Square Wave ◽  
Carbon Paste Electrodes ◽  
Wave Voltammetry ◽  
Pulse Voltammetry

Square wave voltammetry and differential pulse voltammetry have been used for the determination of 2-acetamidofluorene and fluoren-9-ol using carbon paste electrodes, following the study of the influence of the carbon paste composition on the voltammetric signals of the analytes. The methods are based on the oxidation of the above compounds and they include adsorptive accumulation of the analyte on the surface of the working electrode. The limit of detection was 1 μmol l-1for fluoren-9-ol in a medium of 0.1 M H2SO4, and 40 nmol l-1for 2-acetamidofluorene in Britton-Robinson buffer (pH 7).

scholarly journals APPLICATION OF THE BISMUTH FILM ELECTRODE FOR THE DETERMINATION OF SELENIUM IN VITAMINIC COMPLEX BY SQUARE WAVE VOLTAMMETRY

2010 ◽  
Vol 07 (13) ◽  
pp. 6-15
Author(s):  
Joyce Nunes BIANCHIN ◽  
Marcel Silveira dos SANTOS ◽  
Almir SPINELLI
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Copper Electrode ◽  
Analytical Sensitivity ◽  
Bismuth Film ◽  
Analytical Methodology ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Relative Standard

This work was developed an analytical methodology for determination of selenium in samples of vitaminic complex using the square wave voltammetry (SWV). The analysis were performed with a copper electrode modified with bismuth film deposited by applying a potential of -400 mV for 60 seconds in a solution containing HCl 0.2 mol L-1, 20 g L-1 and 500 µg L-1 of Bi(III). The variables: time and conditioning potential were optimized by SWV for the formation of the bismuth film, after that, the variables that affect the analytical sensitivity for the reduction of Se (IV): frequency, increment and high of pulse were also optimized. The linearity of the method ranged from 90 – 1180 µg L-1. Limit of detection of 26,4 µg L-1, quantification limit of 87,9 µg L-1. Analytical frequency of 30 samples/hour. The method showed excellent precision, calculated as the relative standard deviation (RSD%) (n = 5) using spiked solution of 150 µg L-1. The concentration of selenium found in the sample of the vitaminic complex was 24 µg/tablet. A study of recovery was performed resulting in 92%.

scholarly journals Simultaneous Hydrolysis and Detection of Organophosphate by Benzimidazole Containing Ligand-Based Zinc(II) Complexes

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 714
Author(s):  
Gaber A. M. Mersal ◽  
Hamdy S. El-Sheshtawy ◽  
Mohammed A. Amin ◽  
Nasser Y. Mostafa ◽  
Amine Mezni ◽  
...  
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Organophosphorus Compounds ◽  
Organophosphorus Pesticides ◽  
Carbon Paste ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Carbon Past Electrode ◽  
Hydrolysis Of ◽  
Biomimetic Sensor

The agricultural use of organophosphorus pesticides is a widespread practice with significant advantages in crop health and product yield. An undesirable consequence is the contamination of soil and groundwater by these neurotoxins resulting from over application and run-off. Here, we design and synthesize the mononuclear zinc(II) complexes, namely, [Zn(AMB)2Cl](ClO4) 1 and [Zn(AMB)2(OH)](ClO4) 2 (AMB = 2-aminomethylbenzimidazole), as artificial catalysts inspired by phosphotriesterase (PTE) for the hydrolysis of organophosphorus compounds (OPs) and simultaneously detect the organophosphate pesticides such as fenitrothion and parathion. Spectral and DFT (B3LYP/Lanl2DZ) calculations revealed that complexes 1 and 2 have a square-pyramidal environment around zinc(II) centers with coordination chromophores of ZnN4Cl and ZnN4O, respectively. Both 1 and 2 were used as a modifier in the construction of a biomimetic sensor for the determination of toxic OPs, fenitrothion and parathion, in phosphate buffer by square wave voltammetry. The hydrolysis of OPs using 1 or 2 generates p-nitrophenol, which is subsequently oxidized at the surface of the modified carbon past electrode. The catalytic activity of 2 was higher than 1, which is attributed to the higher electronegativity of the former. The oxidation peak potentials of p-nitrophenol were obtained at +0.97 V (vs. Ag/AgCl) using cyclic voltammetry (CV) and +0.88 V (vs. Ag/AgCl) using square wave voltammetry. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of zinc(II) complex 1 and 2 on a carbon paste electrode (CPE). The calibration curve showed a linear response ranging between 1.0 μM (0.29 ppm) and 5.5 μM (1.6 ppm) for fenitrothion and 1.0 μM (0.28 ppm) and 0.1 μM (0.028 ppm) for parathion with a limit of detection (LOD) of 0.08 μM (0.022 ppm) and 0.51 μM (0.149 ppm) for fenitrothion and parathion, respectively. The obtained results clearly demonstrated that the CPE modified by 1 and 2 has a remarkable electrocatalytic activity towards the hydrolysis of OPs under optimal conditions.

scholarly journals Square-wave voltammetric determination of rutin in pharmaceutical formulations using a carbon composite electrode modified with copper (II) phosphate immobilized in polyester resin

2012 ◽  
Vol 48 (4) ◽  
pp. 639-649 ◽  
Author(s):  
Kellen Heloizy Garcia Freitas ◽  
Orlando Fatibello-Filho ◽  
Ivanildo Luiz de Mattos
Keyword(s):  
Modified Electrode ◽  
Composite Electrode ◽  
Polyester Resin ◽  
Pharmaceutical Formulations ◽  
Carbon Composite ◽  
X Ray ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Carbon Composite Electrode

A carbon composite electrode modified with copper (II) phosphate immobilized in a polyester resin (Cu3(PO4)2-Poly) for the determination of rutin in pharmaceutical samples by square-wave voltammetry is described herein. The modified electrode allows the determination of rutin at a potential (0.20 V vs. Ag/AgCl (3.0 mol L-1 KCl)) lower than that observed at an unmodified electrode. The peak current was found to be linear to the rutin concentration in the range from 9.9 × 10-8 to 2.5 × 10-6 mol L-1, with a detection limit of 1.2×10-8 mol L-1. The response of the electrode was stable, with no variation in baseline levels within several hours of continuous operation. The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) system. The results obtained are precise and accurate. In addition, these results are in agreement with those obtained by the chromatographic method at a 95% confidence level.

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