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Papers by Guzel Ziyatdinova

Research paper thumbnail of Evaluation of the Antioxidant Properties and GC-MSD Analysis of Commercial Essential Oils from Plants of the Lamiaceae Family

Učënye Zapiski Kazanskogo Universiteta. Seriâ Estestvennye Nauki, 2023

Plants of the Lamiaceae family have been used for thousands of years in cooking, as well as phyto... more Plants of the Lamiaceae family have been used for thousands of years in cooking, as well as phyto-and aromatherapy. Their essential oils are characterized by high antioxidant and other types of biological activities. In our study, the phytochemical profile and quantification of the essential oil components of thyme, marjoram, and sage were analyzed by gas chromatography with mass-spectrometric detection (GC-MSD). The antioxidant properties of the samples were evaluated using total antioxidant parameters (total antioxidant capacity (TAC), ferric reducing power (FRP), antioxidant activity (AOA) towards 2,2-diphenyl-1-picrylhydrazyl (DPPH • ), and total phenolics by Folin-Ciocalteu method). The obtained FRP was 46-321-fold lower than TAC, which is consistent with the contents of phenolics identified in the samples. Terpenes, isopropylmethylphenols, and eugenol turned out to be the major components of all essential oils and determined their TAC and AOA. The Folin-Ciocalteu method was applicable to the thyme essential oil only. Its FRP, which is based on the reaction of phenolic antioxidants with electrogenerated ferricyanide ions, agreed well with the total phenolic contents (329 ± 17 and 334 ± 15 mg of carvacrol per mL, respectively). The thyme essential oil had the highest antioxidant parameters, while sage showed the weakest antioxidant properties. Positive correlations (r = 0.8846-0.9964) of the antioxidant parameters were obtained.

Research paper thumbnail of A Voltammetric Sensor Based on Carboxylated Carbon Nanotubes and Poly(Pyrogallol Red) for the Determination of Eugenol in Essential Oils

Journal of analytical chemistry, Jun 1, 2024

Research paper thumbnail of Voltammetric Determination of Tannic Acid in Medicinal Plants Using Multi-Walled Carbon Nanotube-Modified Electrode

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Determination of captopril in pharmaceutical forms by stripping voltammetry

A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based o... more A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based on the preliminary electrochemical accumulation of the captopril oxidation product on a platinum electrode in a 0.1 M HNO 3 solution at 1.2 V versus a saturated silver-silver chloride electrode. The reduction current of the oxidation product is a linear function of captopril concentration in the range from 1.2 × 10-6 to 3.2 × 10-4 M. The determination limit is 9.2 × 10-7 M. The relative standard deviation is between 1 and 4%.

Research paper thumbnail of Determination of Total Antioxidant Capacity of Human Plasma from Patients with Lung Diseases Using Constant-Current Coulometry

Eurasian Journal of Analytical Chemistry, Jun 1, 2006

Original coulometric method for total antioxidant capacity (TAC) determination based on the react... more Original coulometric method for total antioxidant capacity (TAC) determination based on the reaction of plasma antioxidants with electrogenerated bromine is developed. TAC is expressed in units of quantity of electricity (Coulombs) spent for titration per a liter of plasma. Coulomb is the universal unit of the TAC measurements because one can express TAC in units of different antioxidants using Faraday constant and the number of electrons involved in the reaction between antioxidant and electrogenerated bromine. The TAC in the plasma being determined for patients with different types of lung diseases is significantly lower than the one for control group. The data obtained by coulometry correlate with results of voltammetric determination based on oxidation of plasma on the glassy carbon electrode (Y=a + bX, where a=-6,7±0,5, b=1,07±0,04, R =0,9934). So, the proposed method could be recommended for clinical laboratories for estimation of antioxidant status and its subsequent correction using additional antioxidant therapy.

Research paper thumbnail of Coulometric titration with electrogenerated oxidants as a tool for evaluation of cognac and brandy antioxidant properties

Food Chemistry, May 1, 2014

Research paper thumbnail of * * * Electrochemical Oxidation of Syringaldehyde on Surfactant-Modified Electrode

Voltammetric behavior of syringaldehyde on a glassy carbon electrode modified with carbon nano- f... more Voltammetric behavior of syringaldehyde on a glassy carbon electrode modified with carbon nano- fibers (CNF/GCE) and surfactants (Surf/CNF/GCE) in Britton-Robinson buffer solution has been studied. The effect of the nature and concentration of a surfactant on its voltammetric characteristics has been evaluated. The anodic (at low surfactant concentrations) and then cathodic (with increase of surfactant concentration) shifts of syringaldehyde oxidation potentials occur independently of surfactant nature. Oxidation currents on Surf/CNF/GCE decrease excluding 0.5 mM cationic cetylpyridinium bromide (CPB), for which the increase of currents by 53% is observed. The electrooxidation scheme of syringal- dehyde on CPB/CNF/GCE is proposed. The process is irreversible with participation of two electrons and two protons and controlled by diffusion. The effect of supporting electrolyte pH and pulse parameters on the analytical signal of syringaldehyde under conditions of differential pulse voltammetry on CPB/CNF/GCE has been studied. The best results have been obtained at pH 2.0, a pulse amplitude of 100 mV and a modulation time of 50 ms. The calibration graphs are linear in the concentration range of 0.75-10 and 10-750 μM with limits of detection and quantification of 0.19 and 0.64 μM, respectively.

Research paper thumbnail of Studies of the Structures of Chemical Compounds and Analytical and Production Control Methods Quantitative Estimation of Benzylisoquinoline Derivatives by Coulometric Titration

Research paper thumbnail of Polyelectrolyte Polyethylenimine–DNA Complexes in the Composition of Voltammetric Sensors for Detecting DNA Damage

Journal of Analytical Chemistry, Feb 1, 2022

A voltammetric DNA sensor based on the polyelectrolyte complexes of polyethylenimine and DNA obta... more A voltammetric DNA sensor based on the polyelectrolyte complexes of polyethylenimine and DNA obtained by self-assembly from solutions of components on a glassy carbon electrode has been developed. Cyclic voltammetry was used to study the preparation conditions and characterize the permeability of the complex for low-molecular-weight redox indicators differing in the mechanism of interaction with DNA (methylene blue and methylene green). The formation of the polyelectrolyte complex was independently confirmed by surface plasmon resonance measurements. The redox peak currents of methylene blue and methylene green varied differently depending on the number of layers of the complex and the nature of the outer layer due to different mechanisms of binding the indicators to DNA molecules and varied assembly density of the complex polyelectrolytes. An increase in the concentration of polyions from 0.1 to 10 μg/mL suppressed the effect of the charge of the outer layer on the indicator currents. Polyelectrolyte coatings were tested to detect specific DNA interactions including intercalation with the anticancer drug doxorubicin and the thermal and chemical denaturation of DNA. It was found that the introduction of decacarboxylated pillar[5]arene into the layer increased the sensitivity of the methylene blue signal to the thermal denaturation of DNA. A comparison between changes in the peak currents of methylene blue and methylene green makes it possible to distinguish the mechanism of DNA damage and separately take into account the contribution of the considered chemical and physical damaging factors. The developed DNA sensor makes it possible to semiquantitatively evaluate the protective effect of antioxidants, which decrease the effect of reactive oxygen species on DNA in the biosensor.

Research paper thumbnail of Sensitive voltammetric quantification of carminic acid in candies using selenium dioxide nanoparticles based electrode

Food Chemistry, Aug 1, 2022

Carminic acid is a food colorant which concentration has to be controlled due to the possible neg... more Carminic acid is a food colorant which concentration has to be controlled due to the possible negative health effects. Sensitive voltammetric method is developed for carminic acid determination using electrode modified with SeO2 nanoparticles (SeO2 NPs) and hexadecyltriphenylphosphonium bromide (HDTPPB) acting as dispersive agent for nanoparticles and electrode surface co-modifier. SeO2 NPs of 37-45 nm are uniformly distributed at the electrode increasing its electroactive area (41 ± 2 vs. 8.9 ± 0.2 mm2 for bare glassy carbon electrode (GCE)). Electrochemical impedance spectroscopy data confirm an 18.3-fold decrease of charge transfer resistance compared to GCE (12.7 ± 0.3 vs. 232 ± 7 kΩ, respectively). In differential pulse mode, the linear dynamic ranges of carminic acid are 0.010-2.5 and 2.5-10 μmol L-1 with a detection limit of 3.4 nmol L-1. The method is successfully employed in candies and lozenges for sore throat treatment. The approach is simple, reliable, and can be used as an alternative to chromatography in routine analysis.

Research paper thumbnail of Prenatal hyperhomocysteinemia induces oxidative stress and accelerates ‘aging’ of mammalian neuromuscular synapses

International Journal of Developmental Neuroscience, Apr 1, 2019

Enhanced levels of homocysteine during pregnancy induce oxidative stress and contribute to many a... more Enhanced levels of homocysteine during pregnancy induce oxidative stress and contribute to many age-related diseases. In this study, we analyzed age-dependent synaptic modifications in developing neuromuscular synapses of rats with prenatal hyperhomocysteinemia (hHCY). One of the main findings indicate that the intensity and the timing of transmitter release in synapses of neonatal (P6 and P10) hHCY rats acquired features of matured synaptic transmission of adult rats. The amplitude and frequency of miniature end-plate currents (MEPCs) and evoked transmitter release were higher in neonatal hHCY animals compared to the control group. Analysis of the kinetics of neurotransmitter release demonstrated more synchronized release in neonatal rats with hHCY. At the same time lower release probability was observed in adults with hHCY. Spontaneous transmitter release in neonates with hHCY was inhibited by hydrogen peroxide (H 2 O 2) whereas in controls this oxidant was effective only in adult animals indicating a higher susceptibility of motor nerve terminals to oxidative stress. The morphology and the intensity of endocytosis of synaptic vesicles in motor nerve endings was assessed using the fluorescence dye FM 1-43. Adult-like synapses were found in neonates with hHCY which were characterized by a larger area of presynaptic terminals compared to controls. No difference in the intensity of FM 1-43 fluorescence was observed between two groups of animals. Prenatal hHCY resulted in reduced muscle strength assessed by the Paw Grip Endurance test. Using biochemical assays we found an increased level of H 2 O 2 and lipid peroxidation products in the diaphragm muscles of hHCY rats. This was associated with a lowered activity of superoxide dismutase and glutathione peroxidase. Our data indicate that prenatal hHCY induces oxidative stress and apparent faster functional and morphological "maturation" of motor synapses. Our results uncover synaptic mechanisms of disrupted muscle function observed in hHCY conditions which may contribute to the pathogenesis of motor neuronal diseases associated with enhanced level of homocysteine.

Research paper thumbnail of 7. Carbon Nanomaterials and Surfactants as Electrode Surface Modifiers in Organic Electroanalysis

De Gruyter eBooks, Mar 19, 2018

Research paper thumbnail of Determination of captopril in pharmaceutical forms by stripping voltammetry

Journal of Analytical Chemistry, Aug 1, 2006

A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based o... more A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based on the preliminary electrochemical accumulation of the captopril oxidation product on a platinum electrode in a 0.1 M HNO3 solution at 1.2 V versus a saturated silver-silver chloride electrode. The reduction current of the oxidation product is a linear function of captopril concentration in the range from

Research paper thumbnail of Electrode Modified with Manganese Dioxide Nanorods for the Simultaneous Voltammetric Determination of Food Colorants

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Selective Voltammetric Sensor for the Simultaneous Quantification of Tartrazine and Brilliant Blue FCF

Sensors, Jan 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Simultaneous voltammetric determination of phenolic antioxidants with chemometric approaches

Electrochimica Acta, Aug 1, 2014

The paper describes the fabrication and application of a novel sensor (a boron-doped diamond elec... more The paper describes the fabrication and application of a novel sensor (a boron-doped diamond electrode modified with Nafion and lead films) for the simultaneous determination of paracetamol and ascorbic acid by differential pulse voltammetry. The main advantage of the lead film and polymer covered borondoped diamond electrode is that the sensitivity of the stripping responses is increased and the separation of paracetamol and ascorbic acid signals is improved due to the modification of the borondoped diamond surface by the lead layer. Additionally, the repeatability of paracetamol and ascorbic acid signals is improved by the application of the Nafion film coating. In the presence of oxygen, linear calibration curves were obtained in a wide concentration range from 5 Â 10 À 7 to 2 Â 10 À 4 mol L À 1 for paracetamol and from 1 Â 10 À 6 to 5 Â 10 À 4 mol L À 1 for ascorbic acid. The analytical utility of the differential pulse voltammetric method elaborated was tested in the assay of paracetamol and ascorbic acid in commercially available pharmaceutical formulations and the method was validated by high performance liquid chromatography coupled with diode array detector.

Research paper thumbnail of Novel voltammetric approaches for lipoic acid quantification in pharmaceutical dosage forms

Proceedings of 7th International Electronic Conference on Medicinal Chemistry, Nov 2, 2021

Research paper thumbnail of Characterization of Essential Oil Antioxidant Properties by Coulometric Titration

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Highly Sensitive Determination of Hesperidin Using Electrode Modified with Poly(Ferulic Acid)

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Poly(Phenol Red)-Based Voltammetric Sensor for the Simultaneous Quantification of Hydroxycinnamic Acids

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Evaluation of the Antioxidant Properties and GC-MSD Analysis of Commercial Essential Oils from Plants of the Lamiaceae Family

Učënye Zapiski Kazanskogo Universiteta. Seriâ Estestvennye Nauki, 2023

Plants of the Lamiaceae family have been used for thousands of years in cooking, as well as phyto... more Plants of the Lamiaceae family have been used for thousands of years in cooking, as well as phyto-and aromatherapy. Their essential oils are characterized by high antioxidant and other types of biological activities. In our study, the phytochemical profile and quantification of the essential oil components of thyme, marjoram, and sage were analyzed by gas chromatography with mass-spectrometric detection (GC-MSD). The antioxidant properties of the samples were evaluated using total antioxidant parameters (total antioxidant capacity (TAC), ferric reducing power (FRP), antioxidant activity (AOA) towards 2,2-diphenyl-1-picrylhydrazyl (DPPH • ), and total phenolics by Folin-Ciocalteu method). The obtained FRP was 46-321-fold lower than TAC, which is consistent with the contents of phenolics identified in the samples. Terpenes, isopropylmethylphenols, and eugenol turned out to be the major components of all essential oils and determined their TAC and AOA. The Folin-Ciocalteu method was applicable to the thyme essential oil only. Its FRP, which is based on the reaction of phenolic antioxidants with electrogenerated ferricyanide ions, agreed well with the total phenolic contents (329 ± 17 and 334 ± 15 mg of carvacrol per mL, respectively). The thyme essential oil had the highest antioxidant parameters, while sage showed the weakest antioxidant properties. Positive correlations (r = 0.8846-0.9964) of the antioxidant parameters were obtained.

Research paper thumbnail of A Voltammetric Sensor Based on Carboxylated Carbon Nanotubes and Poly(Pyrogallol Red) for the Determination of Eugenol in Essential Oils

Journal of analytical chemistry, Jun 1, 2024

Research paper thumbnail of Voltammetric Determination of Tannic Acid in Medicinal Plants Using Multi-Walled Carbon Nanotube-Modified Electrode

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Determination of captopril in pharmaceutical forms by stripping voltammetry

A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based o... more A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based on the preliminary electrochemical accumulation of the captopril oxidation product on a platinum electrode in a 0.1 M HNO 3 solution at 1.2 V versus a saturated silver-silver chloride electrode. The reduction current of the oxidation product is a linear function of captopril concentration in the range from 1.2 × 10-6 to 3.2 × 10-4 M. The determination limit is 9.2 × 10-7 M. The relative standard deviation is between 1 and 4%.

Research paper thumbnail of Determination of Total Antioxidant Capacity of Human Plasma from Patients with Lung Diseases Using Constant-Current Coulometry

Eurasian Journal of Analytical Chemistry, Jun 1, 2006

Original coulometric method for total antioxidant capacity (TAC) determination based on the react... more Original coulometric method for total antioxidant capacity (TAC) determination based on the reaction of plasma antioxidants with electrogenerated bromine is developed. TAC is expressed in units of quantity of electricity (Coulombs) spent for titration per a liter of plasma. Coulomb is the universal unit of the TAC measurements because one can express TAC in units of different antioxidants using Faraday constant and the number of electrons involved in the reaction between antioxidant and electrogenerated bromine. The TAC in the plasma being determined for patients with different types of lung diseases is significantly lower than the one for control group. The data obtained by coulometry correlate with results of voltammetric determination based on oxidation of plasma on the glassy carbon electrode (Y=a + bX, where a=-6,7±0,5, b=1,07±0,04, R =0,9934). So, the proposed method could be recommended for clinical laboratories for estimation of antioxidant status and its subsequent correction using additional antioxidant therapy.

Research paper thumbnail of Coulometric titration with electrogenerated oxidants as a tool for evaluation of cognac and brandy antioxidant properties

Food Chemistry, May 1, 2014

Research paper thumbnail of * * * Electrochemical Oxidation of Syringaldehyde on Surfactant-Modified Electrode

Voltammetric behavior of syringaldehyde on a glassy carbon electrode modified with carbon nano- f... more Voltammetric behavior of syringaldehyde on a glassy carbon electrode modified with carbon nano- fibers (CNF/GCE) and surfactants (Surf/CNF/GCE) in Britton-Robinson buffer solution has been studied. The effect of the nature and concentration of a surfactant on its voltammetric characteristics has been evaluated. The anodic (at low surfactant concentrations) and then cathodic (with increase of surfactant concentration) shifts of syringaldehyde oxidation potentials occur independently of surfactant nature. Oxidation currents on Surf/CNF/GCE decrease excluding 0.5 mM cationic cetylpyridinium bromide (CPB), for which the increase of currents by 53% is observed. The electrooxidation scheme of syringal- dehyde on CPB/CNF/GCE is proposed. The process is irreversible with participation of two electrons and two protons and controlled by diffusion. The effect of supporting electrolyte pH and pulse parameters on the analytical signal of syringaldehyde under conditions of differential pulse voltammetry on CPB/CNF/GCE has been studied. The best results have been obtained at pH 2.0, a pulse amplitude of 100 mV and a modulation time of 50 ms. The calibration graphs are linear in the concentration range of 0.75-10 and 10-750 μM with limits of detection and quantification of 0.19 and 0.64 μM, respectively.

Research paper thumbnail of Studies of the Structures of Chemical Compounds and Analytical and Production Control Methods Quantitative Estimation of Benzylisoquinoline Derivatives by Coulometric Titration

Research paper thumbnail of Polyelectrolyte Polyethylenimine–DNA Complexes in the Composition of Voltammetric Sensors for Detecting DNA Damage

Journal of Analytical Chemistry, Feb 1, 2022

A voltammetric DNA sensor based on the polyelectrolyte complexes of polyethylenimine and DNA obta... more A voltammetric DNA sensor based on the polyelectrolyte complexes of polyethylenimine and DNA obtained by self-assembly from solutions of components on a glassy carbon electrode has been developed. Cyclic voltammetry was used to study the preparation conditions and characterize the permeability of the complex for low-molecular-weight redox indicators differing in the mechanism of interaction with DNA (methylene blue and methylene green). The formation of the polyelectrolyte complex was independently confirmed by surface plasmon resonance measurements. The redox peak currents of methylene blue and methylene green varied differently depending on the number of layers of the complex and the nature of the outer layer due to different mechanisms of binding the indicators to DNA molecules and varied assembly density of the complex polyelectrolytes. An increase in the concentration of polyions from 0.1 to 10 μg/mL suppressed the effect of the charge of the outer layer on the indicator currents. Polyelectrolyte coatings were tested to detect specific DNA interactions including intercalation with the anticancer drug doxorubicin and the thermal and chemical denaturation of DNA. It was found that the introduction of decacarboxylated pillar[5]arene into the layer increased the sensitivity of the methylene blue signal to the thermal denaturation of DNA. A comparison between changes in the peak currents of methylene blue and methylene green makes it possible to distinguish the mechanism of DNA damage and separately take into account the contribution of the considered chemical and physical damaging factors. The developed DNA sensor makes it possible to semiquantitatively evaluate the protective effect of antioxidants, which decrease the effect of reactive oxygen species on DNA in the biosensor.

Research paper thumbnail of Sensitive voltammetric quantification of carminic acid in candies using selenium dioxide nanoparticles based electrode

Food Chemistry, Aug 1, 2022

Carminic acid is a food colorant which concentration has to be controlled due to the possible neg... more Carminic acid is a food colorant which concentration has to be controlled due to the possible negative health effects. Sensitive voltammetric method is developed for carminic acid determination using electrode modified with SeO2 nanoparticles (SeO2 NPs) and hexadecyltriphenylphosphonium bromide (HDTPPB) acting as dispersive agent for nanoparticles and electrode surface co-modifier. SeO2 NPs of 37-45 nm are uniformly distributed at the electrode increasing its electroactive area (41 ± 2 vs. 8.9 ± 0.2 mm2 for bare glassy carbon electrode (GCE)). Electrochemical impedance spectroscopy data confirm an 18.3-fold decrease of charge transfer resistance compared to GCE (12.7 ± 0.3 vs. 232 ± 7 kΩ, respectively). In differential pulse mode, the linear dynamic ranges of carminic acid are 0.010-2.5 and 2.5-10 μmol L-1 with a detection limit of 3.4 nmol L-1. The method is successfully employed in candies and lozenges for sore throat treatment. The approach is simple, reliable, and can be used as an alternative to chromatography in routine analysis.

Research paper thumbnail of Prenatal hyperhomocysteinemia induces oxidative stress and accelerates ‘aging’ of mammalian neuromuscular synapses

International Journal of Developmental Neuroscience, Apr 1, 2019

Enhanced levels of homocysteine during pregnancy induce oxidative stress and contribute to many a... more Enhanced levels of homocysteine during pregnancy induce oxidative stress and contribute to many age-related diseases. In this study, we analyzed age-dependent synaptic modifications in developing neuromuscular synapses of rats with prenatal hyperhomocysteinemia (hHCY). One of the main findings indicate that the intensity and the timing of transmitter release in synapses of neonatal (P6 and P10) hHCY rats acquired features of matured synaptic transmission of adult rats. The amplitude and frequency of miniature end-plate currents (MEPCs) and evoked transmitter release were higher in neonatal hHCY animals compared to the control group. Analysis of the kinetics of neurotransmitter release demonstrated more synchronized release in neonatal rats with hHCY. At the same time lower release probability was observed in adults with hHCY. Spontaneous transmitter release in neonates with hHCY was inhibited by hydrogen peroxide (H 2 O 2) whereas in controls this oxidant was effective only in adult animals indicating a higher susceptibility of motor nerve terminals to oxidative stress. The morphology and the intensity of endocytosis of synaptic vesicles in motor nerve endings was assessed using the fluorescence dye FM 1-43. Adult-like synapses were found in neonates with hHCY which were characterized by a larger area of presynaptic terminals compared to controls. No difference in the intensity of FM 1-43 fluorescence was observed between two groups of animals. Prenatal hHCY resulted in reduced muscle strength assessed by the Paw Grip Endurance test. Using biochemical assays we found an increased level of H 2 O 2 and lipid peroxidation products in the diaphragm muscles of hHCY rats. This was associated with a lowered activity of superoxide dismutase and glutathione peroxidase. Our data indicate that prenatal hHCY induces oxidative stress and apparent faster functional and morphological "maturation" of motor synapses. Our results uncover synaptic mechanisms of disrupted muscle function observed in hHCY conditions which may contribute to the pathogenesis of motor neuronal diseases associated with enhanced level of homocysteine.

Research paper thumbnail of 7. Carbon Nanomaterials and Surfactants as Electrode Surface Modifiers in Organic Electroanalysis

De Gruyter eBooks, Mar 19, 2018

Research paper thumbnail of Determination of captopril in pharmaceutical forms by stripping voltammetry

Journal of Analytical Chemistry, Aug 1, 2006

A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based o... more A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based on the preliminary electrochemical accumulation of the captopril oxidation product on a platinum electrode in a 0.1 M HNO3 solution at 1.2 V versus a saturated silver-silver chloride electrode. The reduction current of the oxidation product is a linear function of captopril concentration in the range from

Research paper thumbnail of Electrode Modified with Manganese Dioxide Nanorods for the Simultaneous Voltammetric Determination of Food Colorants

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Selective Voltammetric Sensor for the Simultaneous Quantification of Tartrazine and Brilliant Blue FCF

Sensors, Jan 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Simultaneous voltammetric determination of phenolic antioxidants with chemometric approaches

Electrochimica Acta, Aug 1, 2014

The paper describes the fabrication and application of a novel sensor (a boron-doped diamond elec... more The paper describes the fabrication and application of a novel sensor (a boron-doped diamond electrode modified with Nafion and lead films) for the simultaneous determination of paracetamol and ascorbic acid by differential pulse voltammetry. The main advantage of the lead film and polymer covered borondoped diamond electrode is that the sensitivity of the stripping responses is increased and the separation of paracetamol and ascorbic acid signals is improved due to the modification of the borondoped diamond surface by the lead layer. Additionally, the repeatability of paracetamol and ascorbic acid signals is improved by the application of the Nafion film coating. In the presence of oxygen, linear calibration curves were obtained in a wide concentration range from 5 Â 10 À 7 to 2 Â 10 À 4 mol L À 1 for paracetamol and from 1 Â 10 À 6 to 5 Â 10 À 4 mol L À 1 for ascorbic acid. The analytical utility of the differential pulse voltammetric method elaborated was tested in the assay of paracetamol and ascorbic acid in commercially available pharmaceutical formulations and the method was validated by high performance liquid chromatography coupled with diode array detector.

Research paper thumbnail of Novel voltammetric approaches for lipoic acid quantification in pharmaceutical dosage forms

Proceedings of 7th International Electronic Conference on Medicinal Chemistry, Nov 2, 2021

Research paper thumbnail of Characterization of Essential Oil Antioxidant Properties by Coulometric Titration

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Highly Sensitive Determination of Hesperidin Using Electrode Modified with Poly(Ferulic Acid)

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Poly(Phenol Red)-Based Voltammetric Sensor for the Simultaneous Quantification of Hydroxycinnamic Acids

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY