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Sacide Altinoz - One of the best experts on this subject based on the ideXlab platform.
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electrochemical behaviour and Voltammetric determination of rosuvastatin calcium in pharmaceutical preparations using a square wave Voltammetric Method
Analytical Methods, 2013Co-Authors: Sacide Altinoz, Banu UyarAbstract:In this study, the electrochemical behaviour of rosuvastatin calcium, which is a hydroxy methyl glutaryl Co-A inhibitor (a member of the statin group), used for the treatment of hypercholesterolemia and dyslipidemia was investigated using cyclic voltammetry (CV) and chronoamperometry (CA) Methods. According to these studies it is assumed that the reaction is a diffusion-controlled process and irreversible. The results from the CA were calculated using Cottrell's equation and the diffusion coefficient was found to be 5.79 × 10−5 ± 0.22 × 10−5 cm2 s−1. It was calculated that 2 electrons were transferred. For the determination of rosuvastatin calcium from the pharmaceutical preparations, a square wave voltammetry (SWV) Method was selected and developed because it is more sensitive and faster than the other Voltammetric Methods. Rosuvastatin calcium's reduction peak was seen at −1184 mV in pH 5 acetate buffer with a hanging mercury drop electrode (HMDE) used as the working electrode, an Ag/AgCl with saturated 3 M KCl reference electrode and a platinum wire counter electrode. 70 Hz frequency, 4 mV scan increment and 25 mV pulse amplitude were chosen as optimum parameters. This Method was validated according to the ICH guidelines on analytical Method validation processes. Linearity for rosuvastatin calcium was found between 0.20 and 10.00 μg mL−1. While the limit of detection for rosuvastatin calcium was 0.07 μg mL−1, the limit of quantitation was 0.20 μg mL−1. As a result of these validation studies, the selective, accurate and precise square wave Voltammetric Method, which gives sensitive and repeatable results, was applied to the determination of rosuvastatin calcium from pharmaceutical preparations. The results obtained from the developed Method were compared with a spectrophotometric Method and a capillary electrophoresis Method reported in the literature and no significant difference was found statistically.
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Square-wave adsorptive stripping Voltammetric determination of candesartan cilexetil in pharmaceutical formulations
Journal of Applied Electrochemistry, 2009Co-Authors: İncilay Süslü, Nuran Özaltın, Sacide AltinozAbstract:A sensitive, simple and rapid square-wave adsorptive stripping Voltammetric Method was developed and validated for the determination of candesartan cilexetil in pharmaceutical formulations. The proposed Method was based on electrochemical reduction of candesartan cilexetil at a hanging mercury drop electrode in phosphate buffer at pH 5.0. A well-defined reduction peak was observed at −1340 mV with 30 s of accumulation time and −1100 mV of accumulation potential. Under these optimized conditions, the square-wave adsorptive stripping Voltammetric peak current showed a linear correlation on drug concentration over the range of 0.25–1.34 µg mL^−1 with a correlation coefficient of 0.9986 for the proposed Method. The detection and quantitation limits for this Method were 1 × 10^−2 and 2.5 × 10^−1 µg mL^−1, respectively. The results obtained for intra-day and inter-day precision (as RSD%) were between 1.10 and 3.90%. This Method was applied successfully for the determination of candesartan cilexetil in its tablet dosage forms with mean recoveries of 101.13 ± 0.78% with RSD of 2.06% for 8 mg tablet and 99.84 ± 0.89% with RSD of 2.36% for 16 mg tablet. The results obtained from the developed square-wave adsorptive stripping Voltammetric Method were compared with those obtained by the analytical Method reported in the literature.
Jaromira Chýlkova - One of the best experts on this subject based on the ideXlab platform.
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Voltammetric determination of mesalazine in pharmaceutical preparations and biological samples using boron-doped diamond electrode
Chemical Papers, 2017Co-Authors: Michaela Štěpánková, Renata Selesovska, Lenka Janikova, Jaromira ChýlkovaAbstract:Voltammetric Method for the determination of non-steroidal anti-inflammatory drug mesalazine (5-ASA) is presented for the first time using boron-doped diamond electrode (BDDE). 5-ASA provides one well-developed SWV oxidation peak at about −900 mV (vs. saturated silver/silver chloride reference electrode) on BDDE. Britton-Robinson buffer (pH 7.0) was chosen as an optimal supporting electrolyte for the determination of 5-ASA using square wave voltammetry (SWV). Parameters of SWV were developed and low limit of detection (7.0 × 10^−7 mol L^−1) was reached. In addition, relative standard deviation of repeated measurements ( c _5-ASA = 5 × 10^−5 mol L^−1, RSD_M = 2.7%) and relative standard deviation of repeated determinations (RSD_D
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sensitive Voltammetric Method for the fast analysis of the antioxidant pyrogallol using a boron doped diamond electrode in biofuels
Chemical Papers, 2017Co-Authors: Jaromira Chýlkova, Renata Selesovska, Marketa Tomaskova, Lenka Janikova, Tomas Navratil, Petra ChudobovaAbstract:A sensitive Voltammetric Method for the determination of pyrogallol (PY) was developed employing a boron-doped diamond electrode (BDDE). The composition of the supporting electrolyte was investigated during the development of the Methodology. Linear sweep voltammetry (LSV) under the optimized experimental conditions was applied for PY determination with a limit of detection and limit of quantification of 0.85 and 2.82 μmol L−1, respectively. These values are satisfactory for application to real samples. The usability of this Method for the quantification of pyrogallol was in range from 2.82 to 296.00 μmol L−1. Finally, the developed Method was successfully used for the analysis of real samples of biodiesel produced from rapeseed oil and its blend with diesel fuel. Samples of biodiesel and biodiesel blends were analyzed directly in an electrochemical cell, while samples with very low concentrations of PY in biodiesel were extracted with water using the proposed simple and fast process.
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sensitive Voltammetric Method for determination of herbicide metribuzin using silver solid amalgam electrode
Monatshefte Fur Chemie, 2016Co-Authors: Lenka Janikova, Renata Selesovska, Marketa Tomaskova, Michaela Rogozinska, Jaromira ChýlkovaAbstract:Voltammetric behavior of triasulfuron (TS), sulfonylurea herbicide, was investigated using mercury meniscus modified silver solid amalgam electrode (m-AgSAE) and hanging mercury drop electrode (HMDE). It was found that TS provided one well-developed reduction peak and the highest current response was recorded in Britton–Robinson buffer of pH 3 (m-AgSAE) and 2.5 (HMDE), respectively. Differential-pulse voltammetry (DPV) with optimized working parameters was applied for analysis of model solutions containing TS with good sensitivity (LD(m-AgSAE) = 6.4 × 10−8 mol L−1 and LD(HMDE) = 2.7 × 10−9 mol L−1, respectively). Proposed Method was successfully applied in analysis of herbicide preparation and river water. © 2013 Elsevier Ltd. All rights reserved.
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sensitive Voltammetric Method for rapid determination of pyridine herbicide triclopyr on bare boron doped diamond electrode
Electrochimica Acta, 2015Co-Authors: Lenka Janikovabandžuchova, Renata Selesovska, Karolina Schwarzovapeckova, Jaromira ChýlkovaAbstract:Abstract Voltammetric Method for the determination of a pyridine herbicide triclopyr (3,5,6-trichloro-2-pyridyloxyacetic acid) is presented for the first time using bare boron-doped diamond electrode. Triclopyr provides one well-developed, pH-independent oxidation signal at ca. +1.9 V (vs. Ag∣AgCl∣KCl (sat.)) contrary to structurally related clopyralid, which is not oxidizable at the working electrode. Britton–Robinson buffer (pH 2.0) was chosen as optimal electrolyte for determination of triclopyr using square wave and differential pulse voltammetry. The latter Method provided slightly better detection limit of 0.82 μmol L −1 and linearity in the concentration range 1.0–108.8 μmol L −1 . Applicability of the proposed Method was verified by analysis of pesticide preparation, spiked water and urine with excellent results.
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sensitive Voltammetric Method for determination of herbicide triasulfuron using silver solid amalgam electrode
Electrochimica Acta, 2013Co-Authors: Lenka Bandžuchova, Renata Selesovska, Tomas Navratil, Jaromira ChýlkovaAbstract:Voltammetric behavior of triasulfuron (TS), sulfonylurea herbicide, was investigated using mercury meniscus modified silver solid amalgam electrode (m-AgSAE) and hanging mercury drop electrode (HMDE). It was found that TS provided one well-developed reduction peak and the highest current response was recorded in Britton–Robinson buffer of pH 3 (m-AgSAE) and 2.5 (HMDE), respectively. Differential-pulse voltammetry (DPV) with optimized working parameters was applied for analysis of model solutions containing TS with good sensitivity (LD(m-AgSAE) = 6.4 × 10−8 mol L−1 and LD(HMDE) = 2.7 × 10−9 mol L−1, respectively). Proposed Method was successfully applied in analysis of herbicide preparation and river water.
Francois Quentel - One of the best experts on this subject based on the ideXlab platform.
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quantification of refractory organic substances in freshwaters further insight into the response of the Voltammetric Method
Analytical and Bioanalytical Chemistry, 2008Co-Authors: Francois Quentel, Montserrat FilellaAbstract:A recently published Method for quantifying refractory organic matter (often referred to as humic substances) in freshwaters was applied to a wide range of International Humic Substance Society (IHSS) humic compounds in order to (i) gain a better understanding of the mechanism of the Voltammetric response which is the basis of the analytical Method and (ii) provide guidance on choosing the optimal standard to be used. At the same time, the sensitivity of the technique has been increased by switching from the pulse mode initially proposed to the square-wave mode. The results obtained show that (i) differences in adsorption onto the electrode rather than differences in complexation strength are responsible for the differences in the intensity of the signal obtained for the different humic compounds, (ii) carboxylate, N- and S-containing groups do not play a role in the Voltammetric signal.
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application of a simple Voltammetric Method to the determination of refractory organic substances in freshwaters
Analytica Chimica Acta, 2006Co-Authors: Vincent Chanudet, Montserrat Filella, Francois QuentelAbstract:A Method based on the peak obtained by adsorptive stripping voltammetry for the complex formed by organic matter in the presence of trace amounts of molybdenum(VI) has been tested for the determination of refractory organic matter, the so-called humic substances, in freshwaters. The Method is rapid and particularly well-adapted to the determination of low amounts of refractory organic matter. It has a detection limit of 2.4 μg C L−1 for 3 min deposition time. The effect of the presence of other types of natural organic matter has been tested. The Method has been applied to a wide variety of freshwaters at different trophic states.
İncilay Süslü - One of the best experts on this subject based on the ideXlab platform.
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Square-wave adsorptive stripping Voltammetric determination of candesartan cilexetil in pharmaceutical formulations
Journal of Applied Electrochemistry, 2009Co-Authors: İncilay Süslü, Nuran Özaltın, Sacide AltinozAbstract:A sensitive, simple and rapid square-wave adsorptive stripping Voltammetric Method was developed and validated for the determination of candesartan cilexetil in pharmaceutical formulations. The proposed Method was based on electrochemical reduction of candesartan cilexetil at a hanging mercury drop electrode in phosphate buffer at pH 5.0. A well-defined reduction peak was observed at −1340 mV with 30 s of accumulation time and −1100 mV of accumulation potential. Under these optimized conditions, the square-wave adsorptive stripping Voltammetric peak current showed a linear correlation on drug concentration over the range of 0.25–1.34 µg mL^−1 with a correlation coefficient of 0.9986 for the proposed Method. The detection and quantitation limits for this Method were 1 × 10^−2 and 2.5 × 10^−1 µg mL^−1, respectively. The results obtained for intra-day and inter-day precision (as RSD%) were between 1.10 and 3.90%. This Method was applied successfully for the determination of candesartan cilexetil in its tablet dosage forms with mean recoveries of 101.13 ± 0.78% with RSD of 2.06% for 8 mg tablet and 99.84 ± 0.89% with RSD of 2.36% for 16 mg tablet. The results obtained from the developed square-wave adsorptive stripping Voltammetric Method were compared with those obtained by the analytical Method reported in the literature.
Montserrat Filella - One of the best experts on this subject based on the ideXlab platform.
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quantification of refractory organic substances in freshwaters further insight into the response of the Voltammetric Method
Analytical and Bioanalytical Chemistry, 2008Co-Authors: Francois Quentel, Montserrat FilellaAbstract:A recently published Method for quantifying refractory organic matter (often referred to as humic substances) in freshwaters was applied to a wide range of International Humic Substance Society (IHSS) humic compounds in order to (i) gain a better understanding of the mechanism of the Voltammetric response which is the basis of the analytical Method and (ii) provide guidance on choosing the optimal standard to be used. At the same time, the sensitivity of the technique has been increased by switching from the pulse mode initially proposed to the square-wave mode. The results obtained show that (i) differences in adsorption onto the electrode rather than differences in complexation strength are responsible for the differences in the intensity of the signal obtained for the different humic compounds, (ii) carboxylate, N- and S-containing groups do not play a role in the Voltammetric signal.
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application of a simple Voltammetric Method to the determination of refractory organic substances in freshwaters
Analytica Chimica Acta, 2006Co-Authors: Vincent Chanudet, Montserrat Filella, Francois QuentelAbstract:A Method based on the peak obtained by adsorptive stripping voltammetry for the complex formed by organic matter in the presence of trace amounts of molybdenum(VI) has been tested for the determination of refractory organic matter, the so-called humic substances, in freshwaters. The Method is rapid and particularly well-adapted to the determination of low amounts of refractory organic matter. It has a detection limit of 2.4 μg C L−1 for 3 min deposition time. The effect of the presence of other types of natural organic matter has been tested. The Method has been applied to a wide variety of freshwaters at different trophic states.
