scholarly journals Electro-catalytic amplified sensor for determination of N-acetylcysteine in the presence of theophylline confirmed by experimental coupled theoretical investigation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohsen Keyvanfard ◽  
Hassan Karimi-Maleh ◽  
Fatemeh Karimi ◽  
Francis Opoku ◽  
Ephraim Muriithi Kiarii ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
High Performance ◽  
Carbon Paste ◽  
Linear Dynamic ◽  
Oxidation Potentials ◽  
Adsorption Energies ◽  
First Time ◽  
Modify Carbon ◽  
Paste Electrode

AbstractThe 1,l/-bis(2-phenylethan-1-ol)ferrocene, 1-butyl-3-methylimidazolium hexafluoro phosphate (BMPF6) and NiO-SWCNTs were used to modify carbon paste electrode (BPOFc/BMPF6/NiO-SWCNTs/CPE), which could act as an electro-catalytic tool for the analysis of N-acetylcysteine in this work. The BPOFc/BMPF6/NiO-SWCNTs/CPE with high electrical conductivity showed two completely separate signals with oxidation potentials of 432 and 970 mV for the first time that is sufficient for the determination of N-acetylcysteine in the presence of theophylline. The BPOFc/BMPF6/NiO-SWCNTs/CPE showed linear dynamic ranges of 0.02–300.0 μM and 1.0–350.0 μM with the detection limit of ~ 8.0 nM and 0.6 μM for the measurement of N-acetylcysteine and theophylline, respectively. In the second part, understanding the nature of interaction, quantum conductance modulation, electronic properties, charge density, and adsorption behavior of N-acetylcysteine on NiO–SWCNTs surface from first-principle studies through the use of theoretical investigation is vital for designing high-performance sensor materials. The N-acetylcysteine molecule was chemisorbed on the NiO–SWCNTs surface by suitable adsorption energies (− 1.102 to − 5.042 eV) and reasonable charge transfer between N-acetylcysteine and NiO–SWCNTs.

Determination of salicylic acid using a highly sensitive and new electroanalytical sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Maliheh Montazarolmahdi ◽  
Mahboubeh Masrournia ◽  
Azizollah Nezhadali
Keyword(s):  
Salicylic Acid ◽  
High Performance ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Working Electrode ◽  
Highly Sensitive ◽  
Paste Electrode

Background: A drug sensor (salicylic acid, in this case) was designed and made up of this research. The senor was made by modification of paste electrode (MPE) with CuO-SWCNTs and 1-hexyl-3-methylimidazolium chloride (HMICl). The MPE/CuO-SWCNTs/HMICl showed catalytic activity for the oxidation signal of salicylic acid in phosphate buffer solution. Methods: Electrochemical methods were used as a powerful strategy for the determination of salicylic acid in pharmaceutical samples. Aiming at this goal, carbon paste electrode was amplified with conductive materials and used as a working electrode. Results: The MPE/CuO-SWCNTs/HMICl was used for the determination of salicylic acid in the concentration range of 1.0 nM – 230 µM using differential pulse voltammetric (DPV) method. At pH=7.0, as optimum condition, the MPE/CuOSWCNTs/HMICl displayed a high-quality ability for the determination of salicylic acid in urine, pharmaceutical serum, and water samples. Conclusion: The MPE/CuO-SWCNTs/HMICl was successfully used as a new and high performance working electrode for the determination of salicylic acid at a nanomolar level and in real samples.

A New Nanostructure Square Wave Voltammetric Platform for Determination of Tert-butylhydroxyanisole in Food Samples

2019 ◽  
Vol 15 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Fatemeh Karimi ◽  
Majede Bijad ◽  
Mohammad Farsi ◽  
Amir Vahid ◽  
Hesam Asari-Bami ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Food Samples ◽  
Linear Dynamic Range ◽  
Carbon Paste ◽  
Square Wave ◽  
Linear Dynamic ◽  
Electro Oxidation ◽  
Paste Electrode

Background: Antioxidants are one of the important additives in food samples due to their role in protecting human cells against the effects of free radicals. The analysis of antioxidants is essential due to the role of antioxidants in improving body health. Objective: A square wave voltammetric sensor was fabricated for the determination of tert-butylhydroxyanisole (TBHA) based on the application of CdO/SWCNTs and 1-methyl-3-butylimidazolium chloride as mediators for the modification of carbon paste electrode (MBCl/CdO/SWCNTs/CPE). The MBCl/CdO/SWCNTs/CPE improved the sensitivity of TBHA ~ 6.7 times and showed a linear dynamic range 0.07-600 µM with detection limit 0.02 µA for the analysis of TBHA. The pH investigation confirmed that electro-oxidation of TBHA occurred by exchanging two electrons and two protons. In addition, the MBCl/CdO/SWCNTs/CPE was used for determination of TBHA in food samples.

scholarly journals First Report for Determination of d-Penicillamine in the Presence of Tryptophan Using a 2-Chlorobenzoyl Ferrocene/Ag-Supported ZnO Nanoplate–Modified Carbon Paste Electrode

2018 ◽  
Vol 101 (1) ◽  
pp. 208-215 ◽  
Author(s):  
Hadi Beitollahi ◽  
Abbas Gholami ◽  
Mohammad Reza Ganjali
Keyword(s):  
Carbon Paste Electrode ◽  
High Selectivity ◽  
Dynamic Range ◽  
Modified Carbon Paste Electrode ◽  
Linear Dynamic Range ◽  
Carbon Paste ◽  
Linear Dynamic ◽  
Wide Linear Dynamic Range ◽  
Paste Electrode

Abstract In this work, a carbon paste electrode modified with Ag-ZnO nanoplates and 2-chlorobenzoyl ferrocene was prepared and applied for the determination of d-penicillamine in the presence of tryptophan. The morphologies of Ag-ZnO nanoplates were examined by scanning electron microscopy. It was found that under an optimum condition (pH 7.0), the oxidation of d-penicillamine at the surface of such an electrode occurs at a potential about 165 mV less positive than that of an unmodified carbon paste electrode. The diffusion coefficient (D = 7.6 × 10−6 cm2/s) and the electron transfer coefficient (α = 0.54) for d-penicillamine oxidation were also determined. The proposed method exhibited a wide linear dynamic range of 0.03–250.0 µM, with an LOD (S/N = 3) of 0.015 µM. Moreover, the modified electrode exhibited good reproducibility and high selectivity, demonstrating its feasibility for the analytical purpose. Lastly, this new sensor was used for the determination of d-penicillamine and tryptophan in real samples.

Voltammetric behavior of 4-acetamidohippuric acid and 4-acetamidobenzoic acid on a disposable carbon electrode and their determination in human urine

2009 ◽  
Vol 74 (3) ◽  
pp. 443-452 ◽  
Author(s):  
Lai-Hao Wang ◽  
Shih-Ying Zeng
Keyword(s):  
Supporting Electrolyte ◽  
Lithium Perchlorate ◽  
Aminobenzoic Acid ◽  
Carbon Paste ◽  
Carbon Paste Electrodes ◽  
Oxidation Potentials ◽  
Voltammetric Behavior ◽  
Acetylated Metabolites ◽  
Paste Electrode

The voltammetric behavior of 4-aminobenzoic acid (PABA) and its acetylated metabolite on glassy carbon, carbon fiber or carbon paste electrodes was investigated in an aqueous supporting electrolyte. 4-Aminohippuric acid (4-AHA), 4-acetamidobenzoic acid (4-AMB) and 4-acetamidohippuric acid (4-Ac-AHA) can be separated on a capillary carbon paste electrode in 0.1 M lithium perchlorate. The oxidation potentials of PABA, 4-AHA, 4-AMB and 4-Ac-AHA were 0.70, 0.88, 1.06 and 1.10 V on capillary CPE, respectively. The electrooxidation process is used for simultaneous quantitative determination of acetylated metabolites in urine.

Development of an HPLC-UV Method for Quantification of Stattic

2019 ◽  
Vol 15 (6) ◽  
pp. 568-573
Author(s):  
Soheil Sedaghat ◽  
Ommoleila Molavi ◽  
Akram Faridi ◽  
Ali Shayanfar ◽  
Mohammad Reza Rashidi
Keyword(s):  
High Performance ◽  
Accurate Method ◽  
Plasma Samples ◽  
Promising Target ◽  
Relative Standard ◽  
Dimerization Inhibitor ◽  
Oncogenic Protein ◽  
First Time ◽  
Transcription 3

Background: Signal transducer and activator of transcription 3 (STAT3), an oncogenic protein found constitutively active in many types of human malignancies, is considered to be a promising target for cancer therapy. Objective: In this study for the first time, a simple and accurate method has been developed for the determination of a STAT3 dimerization inhibitor called stattic in aqueous and plasma samples. Methods: A reverse-phase high-performance liquid chromatography (RP-HPLC) composed of C18 column as stationary phase, and the mixture of acetonitrile (60%) and water (40%) as mobile phase with a UV detection at 215 nm were applied for quantification of stattic. The developed method was validated by Food and Drug Administration (FDA) guideline. Results: The method provided a linear range between 1-40 and 2.5-40 µg mL-1 for aqueous and plasma samples, respectively, with a correlation coefficient of 0.999. The accuracy (as recovery) of the developed method was found to be between 95-105% for aqueous medium and 85-115% for plasma samples. The precision (as relative standard deviation) for aqueous and plasma samples was less than 6% and 15%, respectively. The sensitivity of the developed method based on FDA guideline was 1 µg mL-1 for aqueous and 2.5 µg mL-1 for plasma samples. Conclusion: These results show that the established method is a fast and accurate quantification for stattic in aqueous and plasma samples.

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