scholarly journals Synthesis and Characterization of GO/ZIF-67 Nanocomposite: Investigation of Catalytic Activity for the Determination of Epinine in the Presence of Dobutamine

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 88
Author(s):  
Mahboobeh Shahsavari ◽  
Mojtaba Mortazavi ◽  
Somayeh Tajik ◽  
Iran Sheikhshoaie ◽  
Hadi Beitollahi
Keyword(s):  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Screen Printed Electrode ◽  
Limit Of Quantification ◽  
Diffusion Controlled ◽  
Rate Study ◽  
The Stability

In this study, we prepared graphene oxide (GO)/ZIF-67 nanocomposites. Therefore, GO/ZIF-67 nanocomposites were used as a modifier on a screen-printed electrode (GO/ZIF-67/SPE) for studying the electrochemical behavior of epinine in phosphate buffer saline (PBS) at pH 7.0 with voltammetry techniques. The GO/ZIF-67/SPE showed greater electrocatalytic activities than the bare SPE. As a result, the GO/ZIF-67/SPE was utilized for additional electrochemical examinations. The epinine concentration determination was in the range 9.0 × 10−8 M to 5.0 × 10−4 M, and the limit of detection (LOD) as well as the limit of quantification (LOQ) equaled 2.0 and 6.6 nM, respectively. From the scan rate study, the oxidation of epinine was found to be diffusion-controlled, and the simultaneous detection of epinine and dobutamine were well achieved with the differential pulse voltammetric (DPV) technique. Moreover, the stability and reproducibility of epinine at the GO/ZIF-67/SPE was studied, and the use of the GO/ZIF-67/SPE to detect epinine and dobutamine in real samples was furthermore successfully demonstrated.

scholarly journals Surface-Enhanced Oxidation and Determination of Isothipendyl Hydrochloride at an Electrochemical Sensing Film Constructed by Multiwalled Carbon Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
S. N. Prashanth ◽  
Shankara S. Kalanur ◽  
Nagappa L. Teradal ◽  
J. Seetharamappa
Keyword(s):  
Limit Of Detection ◽  
Biological Fluids ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Good Precision ◽  
Multiwalled Carbon ◽  
Limit Of Quantification ◽  
Surface Enhanced ◽  
Ph Range

The electrochemical behavior of isothipendyl hydrochloride (IPH) was investigated at bare and multiwalled-carbon-nanotube modified glassy carbon electrode (MWCNT-GCE). IPH (55 μM) showed two oxidation peaks in Britton-Robinson (BR) buffer of pH 7.0. The oxidation process of IPH was observed to be irreversible over the pH range of 2.5–9.0. The influence of pH, scan rate, and concentration of the drug on anodic peak was studied. A differential pulse voltammetric method with good precision and accuracy was developed for the determination of IPH in pure and biological fluids. The peak current was found to be linearly dependent on the concentration of IPH in the range of 1.25–55 μM. The values of limit of detection and limit of quantification were noticed to be 0.284 and 0.949 μM, respectively.

scholarly journals Carvacrol electrochemical reaction characteristics on screen printed electrode modified with La2O3/Co3O4 nanocomposite

2019 ◽  
Vol 9 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Sayed Zia Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi
Keyword(s):  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Co3o4 Nanoparticles ◽  
Electrochemical Characteristics ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Voltammetric Techniques ◽  
Screen Printed

Electrochemical characteristics of carvacrol were investigated on a screen-printed electrode (SPE) modified with La2O3/Co3O4 nanocomposite by using voltammetric techniques, which displayed a well-defined peak for sensitive carvacrol determination in phosphate buffer solution (PBS) at pH 7.0. La2O3/Co3O4 nanoparticles demonstrated suitable catalytic activity for carvacrol determination by differential pulse voltammetry (DPV) technique. Besides, determination of carvacrol in a real samples was recognized in the light of electrochemical findings and a validated voltammetric technique for quantitative analysis of carvacrol in a real formulation was proposed. The DPV peak currents were found to be linear in the concentration range of 10.0 to 800.0 μM. The limit of detection (LOD) was found to be 1.0 μM.

scholarly journals New Method for Simultaneous Determination of Microcystins and Cylindrospermopsin in Vegetable Matrices by SPE-UPLC-MS/MS

Toxins ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 406 ◽  
Author(s):  
Leticia Díez-Quijada ◽  
Remedios Guzmán-Guillén ◽  
Ana Prieto Ortega ◽  
María Llana-Ruíz-Cabello ◽  
Alexandre Campos ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Simultaneous Detection ◽  
Ultra Performance Liquid Chromatography ◽  
Limit Of Quantification ◽  
Worldwide Distribution ◽  
Exposure Estimation ◽  
Liquid Chromatography Tandem Mass

Cyanotoxins are a large group of noxious metabolites with different chemical structure and mechanisms of action, with a worldwide distribution, producing effects in animals, humans, and crop plants. When cyanotoxin-contaminated waters are used for the irrigation of edible vegetables, humans can be in contact with these toxins through the food chain. In this work, a method for the simultaneous detection of Microcystin-LR (MC-LR), Microcystin-RR (MC-RR), Microcystin-YR (MC-YR), and Cylindrospermopsin (CYN) in lettuce has been optimized and validated, using a dual solid phase extraction (SPE) system for toxin extraction and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for analysis. Results showed linear ranges (5–50 ng g−1 f.w.), low values for limit of detection (LOD) (0.06–0.42 ng g−1 f.w.), and limit of quantification (LOQ) (0.16–0.91 ng g−1 f.w.), acceptable recoveries (41–93%), and %RSDIP values for the four toxins. The method proved to be robust for the three variables tested. Finally, it was successfully applied to detect these cyanotoxins in edible vegetables exposed to cyanobacterial extracts under laboratory conditions, and it could be useful for monitoring these toxins in edible vegetables for better exposure estimation in terms of risk assessment.

scholarly journals Determination of Atorvastatin with Voltammetric Sensors Based on Nanomaterials

Inventions ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 57
Author(s):  
Ramona Oana Gunache (Roșca) ◽  
Alexandra Virginia Bounegru ◽  
Constantin Apetrei
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Products ◽  
Spectrometric Method ◽  
Background Current ◽  
Limit Of Quantification ◽  
Voltammetric Sensors ◽  
Printed Sensors ◽  
Lower Background

This paper presents an accurate and fast electrochemical method for atorvastatin determination in pharmaceutical products. Two screen-printed sensors, one—carbon based (SPCE) and one based on carbon nanotubes and gold nanoparticles (AuNP-CNT/SPCE) were used during the electrochemical analyses. At all experimental stages, cyclic voltammetry was employed, both for the characterization of the sensors and their electrochemical behavior, and for quantitative determinations. AuNP-CNT/SPCE has showed an extended active area, higher intensity peaks, better reversibility and lower background current than the unmodified sensor. For atorvastatin quantification, a calibration curve has been developed within the 1.2–606.25 µM concentration range. A linearity relation between the current of the anodic peak and concentration has been obtained in the range 1.2–53.33 µMfor both sensors. With the AuNP-CNT/SPCE sensor, low values of limit of detection, LOD (1.92 × 10−7 M) and limit of quantification, LOQ (6.39 × 10−7 M) have been obtained, which demonstrates the feasibility of the method of determining atorvastatin from real samples. Atorvastatin amount has been successfully determined from pharmaceutical products using AuNP-CNT/SPCE. The results were similar to the manufacturer’s specifications regarding the dosage per tablet and to the concentrations obtained by applying the FTIR spectrometric method.

Voltammetric Determination of Diazepam on Antimony Film Screen-Printed Electrode in Pharmaceutical Formulations

2020 ◽  
Vol 16 ◽  
Author(s):  
Vesna Antunović ◽  
Rada Baošić ◽  
Aleksandar Lolić
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Ex Situ ◽  
Screen Printed Electrode ◽  
Limit Of Quantification ◽  
Azomethine Group ◽  
Antimony Film ◽  
Screen Printed

Background: Diazepam belongs to the group of 1,4-benzodiapines. It is used for the treatment of anxiety, convulsions and as a muscle relaxant. The presence of 4,5-azomethine group enables its electrochemical detection Introduction: A screen-printed electrode modified with antimony film was used for the determination of diazepam in pharmaceutical preparations Methods: Electrode modification was done by ex-situ deposition of antimony on commercially available screen-printed electrode. Parameters affecting the electroanalytical response of the sensor, such as deposition potential, deposition time, and antimony concentration, were examined and optimized. The modified electrode showed enhanced electroactivity for diazepam reduction compared to unmodified electrode. Under optimal conditions, linear sweep voltammetry was used for the determination of analyte Results: The sensor showed linear dependence in the range from 0.5 to 10 μmol/L, the correlation coefficient was 0.9992. The limit of detection was 0.33 μmol/L, corresponding limit of quantification was 1.08 μmol/L. Modification enabled determination of diazepam in the presence of oxygen. Conclusion: The modified electrode was used for the determination of diazepam in tablets. Results confirmed the applicability of the electrochemical sensor

Catalytic Cathodic Stripping Voltammetry of 5-Phenyl-1,3,4-oxadiazole-2-thiol in the Presence of Nickel(II) and Cobalt(II) Ions

2004 ◽  
Vol 69 (8) ◽  
pp. 1600-1609
Author(s):  
Sławomira Skrzypek ◽  
Agata Michałek ◽  
Witold Ciesielski ◽  
Michał Kasprzak
Keyword(s):  
Catalytic Reduction ◽  
Limit Of Detection ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Acetate Buffer ◽  
Limit Of Quantification ◽  
Cathodic Stripping Voltammetry ◽  
Region 10 ◽  
Cathodic Stripping

5-Phenyl-1,3,4-oxadiazole-2-thiol (POT) and the systems Ni(II)-POT-acetate buffer, Co(II)-POT-acetate buffer were investigated by differential-pulse cathodic stripping voltammetry (DPCSV). The results of the voltammetric measurements show that POT gives a DPCSV signal at about -0.2 V vs Ag|AgCl. The presence of both POT and nickel(II) ions gives rise to a new peak at about -0.6 V; in the presence of cobalt(II) ions a new peak appears at -1.1 V. Based on published results obtained for other sulfur compounds in the presence of Ni(II) or Co(II) ions, the peak at -0.6 V is ascribed to catalytic reduction of Ni(II), and the peak at -1.1 V to hydrogen catalytic discharge. Optimum conditions have been found for the determination of POT by DPCSV. A linear dependence has been found only for the catalytic Ni(II) peak in the region 10-8-10-7 M POT. The calculated limit of detection and limit of quantification are 3.4 × 10-9 and 1.1 × 10-8 mol l-1, respectively.

scholarly journals Development and Validation of Stability Indicating Reverse Phase High Performace Liquid Chromatography Method for the Determination of Umeclidinium and Vilanterol in Pharmaceutical Dosage Form

2021 ◽  
pp. 208-219
Author(s):  
Ahsaana Hamsa ◽  
K. Praseetha ◽  
K. P. Dijin Raj ◽  
T. V. Ashira ◽  
O. V. Athira ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Dosage Form ◽  
Limit Of Detection ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Pharmaceutical Dosage Form ◽  
Relative Standard ◽  
Validation Parameters ◽  
The Stability

A Sensitive, fast, linear and accurate liquid chromatography technique was developed for the simultaneous determination of Umeclidinium and Vilanterol in Powder dosage form. The estimation was carried out using Phenomenex C18 column (150 × 4.6 mm, 5μ) with ammonium acetate: acetonitrile taken in the ratio 60:40 as mobile phase and pumped at a flow rate of 0.9 ml/min at 300C. Detection wavelength selected was 245 nm. Retention times of Umeclidinium and Vilanterol were found to be 2.219 min and 2.794 min. The method was validated in terms of linearity, precision, accuracy, limit of detection, limit of quantification as per International council for harmonization guidelines. Degradation studies performed indicated the stability of the drug. All of these analytical validation parameters were evaluated, and the percent relative standard deviations were calculated, indicating the method's suitability for determination of Umeclidinium and Vilanterol in pharmaceutical dosage form.

scholarly journals Construction of a simple and selective electrochemical sensor based on Nafion/TiO2 for the voltammetric determination of olopatadine

2021 ◽  
Author(s):  
Mohammad Mehmandoust ◽  
Amirhossein Mehmandoust ◽  
Nevin Erk
Keyword(s):  
High Performance ◽  
Electrochemical Impedance ◽  
Titanium Dioxide Nanoparticles ◽  
Differential Pulse ◽  
Screen Printed Electrode ◽  
Limit Of Quantification ◽  
Transmission Electron ◽  
Performance Ability ◽  
Screen Printed

A selective and facile voltammetric method based on titanium dioxide nanoparticles and Nafion (Nafion/TiO2 NPs) on the screen-printed electrode (SPE) was proposed for olopatadine determination. Followed by the synthesis of TiO2 nanoparticles, various methods, including high-resolution transmission electron microscopy (HR-TEM), ultraviolet-visible spectroscopy (UV-Vis), energy-dispersive X-ray (EDX) Raman spectrum, and electrochemical impedance spectroscopy (EIS) were utilized to characterize the nanomaterials. Nafion/TiO2 on the screen-printed electrode (NFN/TiO2/SPE) was used to determine olopatadine in concentration ranges of 0.01 to 0.07 and 0.07 to 14.6 µM with a limit of quantification as low as 7.0 nM, via differential pulse voltammetry technique. The NFN/TiO2/SPE offered a high-performance ability to determine olopatadine in the eye drop sample with satisfactory recovery data of 98.2–99.0 %. Also, the developed electrode showed good reproducibility, repeatability, and high selectivity features. The obtained results indicate that NFN/TiO2/SPE could be utilized as an appropriate candidate for electrochemical olopatadine sensing.

Spectrophotometeric Determination of Trifluoperazine HCL in Pure Forms and Pharmaceutical Preperations

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi
Keyword(s):  
Standard Method ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Oxidizing Agent ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Cerium Ion ◽  
Blank Solution

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.

scholarly journals A novel LC-MS method development and validation for the determination of phenyl vinyl sulfone in eletriptan hydrobromide

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Indhu Priya Mabbu ◽  
G. Sumathi ◽  
N. Devanna
Keyword(s):  
Method Development ◽  
Limit Of Detection ◽  
Vinyl Sulfone ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Development And Validation ◽  
Phenyl Vinyl

Abstract Background The aim of the present method is to develop and validate a specific, sensitive, precise, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the estimation of the phenyl vinyl sulfone in the eletriptan hydrobromide. The effective separation of the phenyl vinyl sulfone was achieved by the Symmetry C18 (50 × 4.6 mm, 3.5 μm) column and a mobile phase composition of 0.1%v/v ammonia buffer to methanol (5:95 v/v), using 0.45 ml/min flow rate and 20 μl of injection volume, with methanol used as diluent. The phenyl vinyl sulfone was monitored on atomic pressure chemical ionization mode mass spectrometer with positive polarity mode. Results The retention time of phenyl vinyl sulfone was found at 2.13 min. The limit of detection (LOD) and limit of quantification (LOQ) were observed at 1.43 ppm and 4.77 ppm concentration respectively; the linear range was found in the concentration ranges from 4.77 to 27.00 ppm with regression coefficient of 0.9990 and accuracy in the range of 97.50–102.10%. The percentage relative standard deviation (% RSD) for six replicates said to be injections were less than 10%. Conclusion The proposed method was validated successfully as per ICH guidelines. Hence, this is employed for the determination of phenyl vinyl sulfone in the eletriptan hydrobromide.

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