scholarly journals Voltammetric methods of reboxetine analysis and the mechanism of its electrode reactions

2013 ◽  
Vol 11 (5) ◽  
pp. 706-716 ◽  
Author(s):  
Deniz Altunöz-Erdoğan ◽  
Nevin Erk ◽  
Esma Kılıç
Keyword(s):  
Protein Binding ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Cathodic Peak ◽  
Glassy Carbon Electrodes ◽  
Wave Voltammetry ◽  
Diffusion Controlled ◽  
Electrochemical Redox ◽  
Voltammetric Methods ◽  
Drug Protein Binding

AbstractReboxetine (RBX) electrochemical redox behavior at hanging mercury drop (HMDE) and glassy carbon electrodes (GCE) was studied in various pH Britton-Robinson universal buffers using cyclic voltammetry and square-wave voltammetry. RBX was reduced at the HMDE and oxidized at the GCE with reversible adsorption controlled and irreversible diffusion controlled processes respectively. The anodic peak is due to the amine and the cathodic peak may correspond to oxygen protonation. An oxidation reaction mechanism is proposed. The linear relation between peak currents and RBX concentration allowed simple, sensitive, precise and inexpensive voltammetric procedures to be developed. The limit of detection was 0.04 µM RBX. The procedures were successfully applied to human urine and RBX tablet assay. Therapeutic RBX concentrations in human serum were not detected due to strong drug-protein binding. Using bovine serum albumin, the methods were used to investigate the effect of serum protein binding on RBX determination.

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.

New PGE Modified Electrode Comprising Ni NPs/1,5-Diphenylcarbazide Film Capable for Analyzing Oxytocin

2020 ◽  
Vol 18 (11) ◽  
pp. 793-800
Author(s):  
Mahsa JaFari-Pouyani ◽  
Samineh Kaki ◽  
Arash Babakhanian
Keyword(s):  
Cyclic Voltammetry ◽  
Linear Response ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Nano Particles ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Microscopy Techniques ◽  
Bare Surface ◽  
Human Blood Serum Sample

This study focuses on the compatibility of square wave voltammetry technique with new modified graphite pencil electrode to quantify Oxytocin. Ni-Nano particles and 1,5-diphenylcarbazide modifiers were quickly electro-deposited by cyclic voltammetry sweeping technique on the bare surface of a graphite pencil electrode. The electrochemical and morphological assessments were accomplished with cyclic voltammetry, square wave voltammetry and scanning electron microscopy techniques. The proposed electrochemical sensor revealed a good electro catalytic response to Oxytocin concerning the parameters α = 0.42, log Ks =3.44 and Γ = 8.72×10−10 in the optimized pH of 4 and the working potential of about 0.35 V. The new sensor also exhibited a linear response to Oxytocin over the concentration range of 125 to 350 nmolL−1 with the limit of detection of 41.53 nmolL−1. Moreover, the applicability of the proposed sensor was successfully examined and it became usable to determine Oxytocin accurately and precisely in real samples such as human blood serum sample without any serious side interference.

Investigations on the Reduction of Molecular Oxygen on Polyphenol Oxidase-Modified Electrode

2005 ◽  
Vol 70 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Hui Jiang ◽  
Chun-Hua Shi ◽  
Yong-Shu Xie ◽  
Qing-Liang Liu
Keyword(s):  
Polyphenol Oxidase ◽  
Transfer Process ◽  
Square Wave Voltammetry ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Cathodic Peak ◽  
Wave Voltammetry ◽  
Nicotiana Tobacum ◽  
Optimum Salt Concentration ◽  
Proton Transfer Process

Polyphenol oxidase (PPO, E.C.1.10.3.1) from Nicotiana tobacum, PPO II, shows a different behavior from that of PPOs from other sources. A one-electron oxygen reduction on PPO II - Nafion modified glassy carbon electrode surface has been observed by square-wave voltammetry. The cathodic peak has been found to be proportional to the concentration of dissolved oxygen. The optimum salt concentration was 0.2 mol/l. The study of its dependence on pH (4-9) indicates that the reduction of oxygen is accompanied by a one-proton-transfer process. Temperature shows little influence on the cathodic peak. The electrode storage has also been studied to evaluate its stability.

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 Sensitive Voltammetric Detection of Chloroquine Drug by Applying a Boron-Doped Diamond Electrode

2020 ◽  
Vol 6 (4) ◽  
pp. 75
Author(s):  
Geiser Gabriel Oliveira ◽  
Déborah Christine Azzi ◽  
Tiago Almeida Silva ◽  
Paulo Roberto de Oliveira ◽  
Orlando Fatibello-Filho ◽  
...  
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Boron Doped Diamond ◽  
Bdd Electrode ◽  
Diamond Electrode ◽  
Boron Doped ◽  
Wave Voltammetry ◽  
Boron Doped Diamond Electrode ◽  
Analytical Curve ◽  
Voltammetric Detection

In this research, a boron-doped diamond (BDD) electrode has been explored to detect the chloroquine drug. The electrochemical performance of BDD electrode towards the irreversible anodic response of chloroquine was investigated by subjecting this electrode to the cathodic (−0.5 A cm−2 by 180 s, generating a predominantly hydrogen-terminated surface) and anodic (+0.5 A cm−2 by 30 s, oxygen-terminated surface) pretreatments. The cathodically pretreated BDD electrode ensured a better-defined anodic peak and higher current intensity. Thus, by applying the cathodically pretreated BDD electrode and square-wave voltammetry (SWV), the analytical curve was linear from 0.01 to 0.25 µmol L−1 (correlation coefficient of 0.994), with sensitivity and limit of detection of 12.2 µA L µmol−1 and 2.0 nmol−1, respectively. This nanomolar limit of detection is the lowest recorded so far with modified and unmodified electrodes.

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.

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.

scholarly journals Electrochemical detection of chlorpheniramine maleate in the presence of an anionic surfactant and its analytical applications

2017 ◽  
Vol 95 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Nagaraj Shetti ◽  
Deepti Nayak
Keyword(s):  
Anionic Surfactant ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Linear Calibration ◽  
Chlorpheniramine Maleate ◽  
Point Of Interest ◽  
Wave Voltammetry ◽  
Diffusion Controlled ◽  
Charge Transfer Coefficient

Improvement of methods for the detection of an analyte at a low concentration with high sensitivity has become an important point of interest. An effort has been made to know the electrochemical behavior of chlorpheniramine maleate in the presence of an anionic surfactant. Voltammograms were obtained in the range of 6.0–11.2 pH, and the maximum peak current (IP) was observed at pH 10.4. Various physicochemical parameters were estimated, including the process on the surface of the electrode, which was found to be diffusion controlled, heterogeneous rate constant, number of electrons transferred, and charge transfer coefficient. Square wave voltammetry of chlorpheniramine maleate at the modified electrode exhibited a linear calibration curve in the concentration range of 1.0–100 μmol/L, with a limit of detection of 28 nmol/L. The proposed technique was successfully used for the determination of chlorpheniramine maleate in pharmaceuticals, as well as in biological samples.

scholarly journals A simple and fast method to detect freebase cocaine in artificial saliva by square wave voltammetry (SWV) using carbon paste electrode

2020 ◽  
Vol 10 (4) ◽  
pp. 361-371
Author(s):  
Bruno Ferreira ◽  
Leandro Oka Duarte ◽  
Érica Naomi Oiye ◽  
Maria Fernanda Muzetti Ribeiro ◽  
Juliana Midori Toia Katayama ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Artificial Saliva ◽  
Fast Method ◽  
Carbon Paste ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Analytical Curve ◽  
Paste Electrode

The consequences of consuming and commercializing illicit drugs including cocaine, con­stitute a serious problem for authorities and the whole society. Cocaine is usually identified in the laboratory conditions by chromatographic or spectroscopic methods. Electro­che­mical techniques have also gained prominence because they are fast and easy to use, have many applications, and provide reproducible and reliable results. Therefore, in the present study, a voltammetric method was developed to detect freebase cocaine using carbon paste electrode and methanol as the main cocaine solvent. The developed method was applied to detect cocaine in the artificial saliva by the square wave voltammetry (SWV). The current values increased linearly with the concentration of cocaine, which afforded construction of the analytical curve. The limit of detection (LoD) and the limit of quantify­cation (LoQ) were determined as 0.90 µg/mL and 2.41 µg/mL, respectively. For compa­rison purposes, HPLC-DAD chromatographic method was also applied to detect cocaine. The corresponding analytical curve gave LoD = 0.043 µg/mL and LoQ = 0.130 µg/mL. Although showing better analytical results, HPLC-DAD method could not detect cocaine in saliva samples without previous treatment, what makes the electrochemical method much more attractive for this type of detection.

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