scholarly journals Direct chronopotentiometric analysis of riboflavin using a glassy carbon vessel as the working electrode

2016 ◽  
pp. 143-151
Author(s):  
Tanja Brezo ◽  
Zorica Stojanovic ◽  
Zvonimir Suturovic ◽  
Snezana Kravic ◽  
Jovana Kos ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Relative Sensitivity ◽  
Working Electrode ◽  
Limit Of Quantitation ◽  
Experimental Parameters ◽  
Hplc Analyses ◽  
Process Vessel

A new method for the determination of riboflavin (vitamin B2) was developed based on chronopotentiometry with a glassy carbon process vessel macroelectrode. The method optimisation included investigation of the most important experimental parameters: type and concentration of the supporting electrolyte, initial potential, reduction current, and the working electrode surface area. The reduction signal of riboflavin appeared at about -0.12 V vs. Ag/AgCl (3.5 mol/dm3 KCl) electrode in 0.025 mol/dm3 HCl as the supporting electrolyte. A linear response was obtained in the the range of 0.05-4 mg/dm3. The limit of detection and limit of quantitation were 0.018 mg/dm3 and 0.054 mg/dm3, respectively. Due to the use of specific working electrode, a significant enhancement of the method relative sensitivity of about 10 times was achieved. The accuracy of the defined method was confirmed by HPLC analyses. The developed method was successfully applied for the quantitation of riboflavin in various pharmaceutical multivitamin preparations.

scholarly journals Voltammetric determination of imidacloprid and thiamethoxam

2005 ◽  
Vol 70 (5) ◽  
pp. 735-743 ◽  
Author(s):  
Valeria Guzsvány ◽  
Ferenc Gaál ◽  
Luka Bjelica ◽  
Silvija Ökrész
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
Limit Of Detection ◽  
Voltammetric Determination ◽  
Polarization Mode ◽  
Voltammetric Method ◽  
Surface Pretreatment ◽  
Working Electrode ◽  
Limit Of Quantitation

A simple voltammetric method using a glassy carbon working electrode was developed for the determination of two members from the neonicotinoid group of insecticides: imidacloprid and thiamethoxam. The experiments showed that the voltammetric response depends on the mode of electrode surface pretreatment and the polarization mode. The response appeared to be linear in the range from 0.028 to 0.50 mg/cm3 for both analyses. The limit of detection was 0.0077 mg/cm3 for imidacloprid and 0.0085 mg/cm3 for thiamethoxam, the limit of quantitation was 0.026 mg/cm3 and 0.028 mg/cm3, respectively. The developed method was applied for the determination of these insecticides in potato samples sprayed with Confidor 200-SL or Actara 25-WG as well as commercial formulations of imidacloprid and thiamethoxam. A recovery trial was performed to assess the accuracy of the results, the recovery values being between 95?102 % for both of neonicotinoids.

scholarly journals Voltammetric Determination of Ascorbic Acid in Pharmaceutical Formulations Using Modified Iodine-Coated Platinum Electrode

Revista Vitae ◽  
2021 ◽  
Vol 28 (2) ◽  
Author(s):  
Mohammad Amayreh ◽  
Wafa Hourani ◽  
Mohammed Khair Hourani
Keyword(s):  
Ascorbic Acid ◽  
Platinum Electrode ◽  
Limit Of Detection ◽  
Statistical Tests ◽  
Supporting Electrolyte ◽  
Pharmaceutical Formulations ◽  
Cyclic Voltammograms ◽  
Limit Of Quantitation ◽  
Significant Difference

Background: Despite the high reactivity of the platinum electrode, the iodine-coated platinum electrode shows obvious inertness toward adsorption and surface processes. For that, iodine-coated platinum electrodes accommodate themselves to interesting voltammetric applications. Objectives: This study reports using the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for ascorbic acid determination in pharmaceutical formulations. Methods: The developed voltammetric method based on recording cyclic voltammograms of ascorbic acid at iodine-coated electrode The optimized experimental parameters for the determination of ascorbic acid were using 0.1 M KCl as a supporting electrolyte with a scan rate of 50mV/s. Results: The anodic peak related to ascorbic acid oxidation was centered at nearly 0.28V. An excellent and extended linear dependence of the oxidative peak current on the concentration of ascorbic acid was observed in the range 2.84x10-3 - 5.68 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.0 µM and 3.01 µM, respectively, attesting to the method’s sensitivity. The investigation for the effect of potential interference from multivitamin tablet ingredients (vitamins B1, B6, B12, folic acid, citric acid, sucrose, glucose, and zinc) indicated specific selectivity toward ascorbic acid and the absence of any electrochemical response toward these components. Recovery results in the range 98.93±2.78 - 99.98±5.20 for spiked standard ascorbic acid in pharmaceutical formulations further confirmed the potential applicability of the developed method for the determination of ascorbic acid in real samples. Conclusions: The developed method was successfully applied to the analysis of ascorbic acid (vitamin C), and the obtained results were in good agreement with the labeled values; besides, the statistical tests indicated no significant difference at p=0.05 with a 95% confidence level.

scholarly journals Anodic Stripping Voltammetric Determination Of Copper In Multivitamin-Mineral Formulations Using Iodine-Coated Platinum Electrode

2021 ◽  
Vol 16 (1) ◽  
pp. 48-56
Author(s):  
Mohammad Amayreh ◽  
Wafa Hourani ◽  
Mohammed Khair Hourani
Keyword(s):  
Platinum Electrode ◽  
Limit Of Detection ◽  
Statistical Tests ◽  
Supporting Electrolyte ◽  
Copper Oxidation ◽  
Copper Determination ◽  
Limit Of Quantitation ◽  
Significant Difference ◽  
Determination Of Copper

In this work, the utilization of the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for copper determination in pharmaceutical formulations was reported. The optimized experimental parameters for the determination of copper were using 0.1M KCl as a supporting electrolyte with a scan rate of 50 mV/s, deposition potential of - 0.2 V, and a deposition time of 2 minutes. The anodic peak related to Copper oxidation is centered at about + 0.05 V. The extended detected linear range for the developed method was between 1 ppm and 100 ppm. The anodic current showed excellent linearity with R2 = 0.9986. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.115 ppm and 0.346 ppm, respectively, which attests to the sensitivity of the method. The investigation for the effect of potential interferences from multivitamins tablet ingredients indicated a specific selectivity toward copper and the absence of any electrochemical response toward these components. The developed method was successfully applied to analyze copper and the obtained results were in good agreement with the labeled values, besides that, the statistical tests indicated no significant difference at p = 0.05 with 95 % confidence level.

scholarly journals Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode

2021 ◽  
Vol 16 (2) ◽  
pp. 103-111
Author(s):  
Mohammad Amayreh ◽  
Wafa Hourani ◽  
Mohammed Khair Hourani
Keyword(s):  
Platinum Electrode ◽  
Limit Of Detection ◽  
Statistical Tests ◽  
Supporting Electrolyte ◽  
Pharmaceutical Formulations ◽  
Calibration Graph ◽  
Polycrystalline Platinum ◽  
Limit Of Quantitation ◽  
Significant Difference

In this work the modified iodine-coated polycrystalline platinum electrode was used to develope a voltammetric sensor for paracetamol determination in pharmaceutical formulations. The optimized experimental parameters for the determination of paracetamol were using 0.5 M H2SO4 as a supporting electrolyte with a scan rate of 50 mV/s. The anodic peak related to paracetamol oxidation was centered at about +0.60 V. The extended calibration graph was constructed between 1 ppm and 500 ppm. The anodic current showed excellent linearity with R2 = 0.9985. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.046 and 0.139 ppm, respectively, which attests to the sensitivity of the method. The investigation for the effect of potential interferences from the content of tablet matrices indicated a specific selectivity toward paracetamol and the absence of any electrochemical response toward these components. The developed method was successfully applied to analysis paracetamol in three brands of pharmaceutical formulations and the obtained results were in good agreement with the labeled values, besides that, the statistical tests indicated no significant difference at p = 0.05 with a 95 % confidence level.

Differential Pulse Anodic Stripping Voltammetric Determination of Cadmium(II) at a Glassy Carbon Electrode Modified with a Nano-TiO2/Chitosan Composite Film

2008 ◽  
Vol 61 (12) ◽  
pp. 1000 ◽  
Author(s):  
Zhimin Xie ◽  
Junjie Fei ◽  
Meihua Huang
Keyword(s):  
Composite Film ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Chemically Modified Electrode ◽  
Nano Tio2 ◽  
Chemically Modified

A simple and effective chemically modified electrode for the determination of cadmium(ii) was developed. The chemically modified electrode was prepared by modifying nano-TiO2/chitosan (nano-TiO2/CS) composite film onto a glassy carbon (GC) electrode. Compared with a bare GC electrode and a CS film-modified GC electrode, the nano-TiO2/CS composite film-coated GC electrode significantly improved the sensitivity of determining CdII. The effects of experimental parameters such as modifier composition in the GC electrode, pH of supporting electrolyte, accumulation potential and time were studied for analytical application. Under the optimized working conditions, the peak currents were linear with concentration over the range from 1.0 × 10–9 to 1.0 × 10–6 mol L–1 for CdII. The limit of detection is 2.0 × 10–10 mol L–1 CdII for 180-s accumulation. The application for the assay of trace levels of CdII in real water samples indicates that it is an economical and potent method.

Simultaneous Determination of Four Herbicide and Pesticide Residues in Chinese Green Tea Using QuEChERS Purification Procedure and UPLC-MS/MS Analysis

2013 ◽  
Vol 634-638 ◽  
pp. 1586-1590
Author(s):  
Su Fang Wang ◽  
Shou Jie Zhang ◽  
Chun Hong Dong ◽  
Guo Qing Wang ◽  
Jun Feng Guo ◽  
...  
Keyword(s):  
Formic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Limit Of Detection ◽  
Multiple Reaction Monitoring ◽  
Graphitized Carbon Black ◽  
Ms Analysis ◽  
Relative Standard ◽  
Limit Of Quantitation

A method for simultaneous determination of residuals of four herbicides and pesticides, simazine, carboxin, diflubenzuron and rotenone, in Chinese green tea was developed. In the proposed method, the tea powder was placed in a centrifuge tube with a plug, extracted in saturated aqueous sodium chloride solution and acetonitrile, agitated using vortex oscillator, and then centrifuged 5 min at 4000 rpm. The supernatant solution was purified by primary secondary amine (PSA) sorbent, C18 power, and graphitized carbon black powder, respectively. Then the purified extracts were dissolved with acetonitrile:0.1% formic acid aqueous solution (40:60, V/V) and agitated, filtered using a syringe with 0.22 μm nylon filter prior to UPLC-MS/MS analysis. The UPLC analysis was performed on an ACQUITY UPLC® HSS T3 column (2.1 mm×100 mm, 1.8 µm), using acetonitrile-0.1% formic acid as mobile phase with the flow rate as 0.3 mL•min-1. Injection volume was 10 µL. Positive ionization mode was applied, and the ions were monitored in the multiple reaction monitoring (MRM) mode with curtain gas 0.069 MPa, collision gas 0.052 MPa, ESI ion spray voltage 5000 V, temperature 550 °C, nebulizer gas 0.24 MPa, and turbo gas 0.28 MPa. The limit of detection (LOD) and limit of quantitation (LOQ) of the proposed method are 1 μg•kg-1and 5 μg•kg-1, respectively. The average recoveries of the four pesticides at 10, 20, and 50 µg•kg-1spiking levels range from 77.4% to 95.3%. TheSupersSuperscript textcript textrelative standard deviation (RSD) (n=6) range form 11.83% to 4.52%.

scholarly journals STABILITY INDICATING HPLC METHOD FOR DETERMINATION OF VILAZODONE HYDROCHLORIDE

2017 ◽  
Vol 9 (4) ◽  
pp. 123
Author(s):  
Birva A. Athavia ◽  
Zarna R. Dedania ◽  
Ronak R. Dedania ◽  
S. M. Vijayendra Swamy ◽  
Chetana B. Prajapati
Keyword(s):  
Limit Of Detection ◽  
Degradation Products ◽  
Hplc Method ◽  
Alkaline Condition ◽  
Forced Degradation ◽  
Molecular Formula ◽  
Stability Indicating ◽  
Dry Heat ◽  
Limit Of Quantitation

Objective: The aim and objective of this study was to develop and validate Stability Indicating HPLC method for determination of Vilazodone Hydrochloride.Methods: The method was carried out on a Phenomenex, C18 (250x4.6 mm, 5 µm) Column using a mixture of Acetonitrile: Water (50:50v/v), pH adjusted to 3.3 with Glacial Acetic Acid for separation. The flow rate was adjusted at 1 ml/min and Detection was carried out at 240 nm.Results: The retention time of vilazodone hydrochloride was found to be 2.3 min. The calibration curve was found to be linear in the range 25-75µg/ml with a correlation coefficient (R2=0.996). The limit of detection and limit of quantitation were found to be 4.78µg/ml and 14.48µg/ml respectively. The % recovery of vilazodone hydrochloride was found to be in the range of 98.21±0.08 % to 99.07±0.64%. The proposed method was successfully applied for the estimation of vilazodone hydrochloride in marketed tablet formulation.Vilazodone Hydrochloride was subjected to forced degradation under Acidic, Alkaline, Oxidation, Dry Heat and Photolytic degradation conditions. Vilazodone hydrochloride showed 3.12% degradation under acidic condition, 4.78% under alkaline condition, 7.8% under oxidation condition, 3.53% under dry heat condition and 4.9% under photolytic condition.Acid degradation impurity was identified and characterised by LC-MS/MS was found to be 1-(4-Penten-1-yl) piperazine having molecular weight 154.253 (m/z 155.08) and Molecular Formula C9H18N2.Conclusion: A simple, precise, rapid and accurate Stability Indicating HPLC method has been developed and validated for the determination of Vilazodone Hydrochloride in presence of its degradation products as per the ICH Guidelines. 

scholarly journals SENSITIVE DETERMINATION OF RELATED SUBSTANCES IN PIOGLITAZONE HYDROCHLORIDE BY HPLC

2017 ◽  
Vol 9 (2) ◽  
pp. 34
Author(s):  
N. Balaji ◽  
Sayeeda Sultana
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Internal Diameter ◽  
Related Substances ◽  
Relative Standard ◽  
Limit Of Quantitation

Objective: An efficient, high performance liquid chromatographic method has been developed and validated for the quantification of related substances in pioglitazone hydrochloride drug substance.Methods: This method includes the determination of three related substances in pioglitazone hydrochloride. The mobile phase A is 0.1% w/v triethylamine in water with pH 2.5 adjusted by dilute phosphoric acid. The mobile phase B is premixed and degassed mixtures of acetonitrile and methanol. The flow rate was 1 ml/min. The elution used was gradient mode. The HPLC column used for the analysis was symmetry C18 with a length of 250 mm, the internal diameter of 4.6 mm and particle size of 5.0 microns.Results: The developed method was found to be linear with the range of 0.006-250% with a coefficient of correlation 0.99. The precision study revealed that the percentage relative standard deviation was within the acceptable limit. The limit of detection and limit of quantitation of the impurities was less than 0.002%and 0.006% with respect to pioglitazone hydrochloride test concentration of 2000 µg/ml respectively. This method has been validated as per ICH guidelines Q2 (R1).Conclusion: A reliable, economical HPLC method was magnificently established for quantitative analysis of related substances of pioglitazone hydrochloride drug substance.

scholarly journals Determination of Simvastatin by Voltammetry Method at Screen-Printed Electrode Modified by Graphene Oxide Nanosheets and Sodium Dodecyl Sulfate

2022 ◽  
Author(s):  
Abolfazl Darroudi ◽  
Saeid Nazari ◽  
Seyed Ali Marashi ◽  
Mahdi Karimi-Nazarabad
Keyword(s):  
Graphene Oxide ◽  
Sodium Dodecyl Sulfate ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Screen Printed Electrode ◽  
Support Electrolyte ◽  
Limit Of Quantitation ◽  
Dodecyl Sulfate ◽  
Screen Printed

Abstract An accurate, rapid, simple, and novel technique was developed to determine simvastatin (SMV). In this research, a screen-printed electrode (SPE) was deposited with graphene oxide (GO) and sodium dodecyl sulfate (SDS), respectively. For the first time, the handmade modified SPE measured the SMV by differential pulse voltammetry (DPV) with high sensitivity and selectivity. The results of cyclic voltammetry indicated the oxidation irreversible process of SMV. Various parameters (pH, concentration, scan rate, support electrolyte) were performed to optimize the conditions for the determination of SMV. Under the optimum experiment condition of 0.1 M KNO3 as support electrolyte and pH 7.0, the linear range was achieved for SMV concentration from 1.8 to 36.6 µM with a limit of detection (LOD), and a limit of quantitation (LOQ) of 0.06 and 1.8 µM, respectively. The proposed method was successfully utilized to determine SMV in tablets and urine samples with a satisfactory recovery in the range of 96.2 to 103.3%.

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