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A New Approach to Determining the Drug Guaifenesin Using Voltammetric and Flow Injection Analysis
Kelíšková, P.; Matvieiev, O.; Sokolová, Romana; Janíková, L.; Behúl, M.; Šelešovská, R.
2024 - anglický
This study presents a new method for detecting guaifenesin (GFE) in pharmaceutical samples. We employed screen-printed sensors with a boron-doped diamond electrode (BDDE) to develop and validate both voltammetric and flow amperometric methods. These approaches were effectively used to analyze model solutions, pharmaceutical preparations, and serum samples spiked with GFE, producing accurate results comparable to those obtained with HPLC/DAD analysis. The developed methods provide straightforward, sensitive, and selective means for determining GFE in various sample matrices, underscoring the potential of SP/BDDE in electrochemical analysis.
Klíčová slova:
guaifenesin; screen-printed sensor; boron-doped diamond electrode
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
A New Approach to Determining the Drug Guaifenesin Using Voltammetric and Flow Injection Analysis
This study presents a new method for detecting guaifenesin (GFE) in pharmaceutical samples. We employed screen-printed sensors with a boron-doped diamond electrode (BDDE) to develop and validate both ...
Optimization of Parameters Used in the Application of Elimination Voltammetry with Linear Scan
Navrátil, Tomáš; Trnková, L.; Hrdlička, Vojtěch; Li, X.
2024 - anglický
Elimination Voltammetry with Linear Scan (EVLS) is a well-established mathematical method that aids in understanding an analyzed electrochemical system. In almost 30 years since its derivation, it has become a “black-box” technique that is applied automatically (in most cases due to its incorporation into a voltammetric software) without thinking about its fundamentals. However, the choice of optimum parameters under which DC voltammetric data (from which elimination curves are calculated) is crucial. This contribution deals with revealing the optimum ratio of applied scan rates and their absolute values (i.e., times of recording) in dependence on the character of the investigated system (diffusion-controlled process, adsorption-controlled process, etc.).
Klíčová slova:
elimination voltammetry with linear scan; optimization; adsorption
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Optimization of Parameters Used in the Application of Elimination Voltammetry with Linear Scan
Elimination Voltammetry with Linear Scan (EVLS) is a well-established mathematical method that aids in understanding an analyzed electrochemical system. In almost 30 years since its derivation, it has ...
Application of In situ TR Spectroelectrochemical Techniques in Determination of Redox Mechanism of Bioactive Compounds
Sokolová, Romana; Jiroušková, Eliška; Degano, I.; Wantulok, J.; Nycz, J.
2023 - anglický
The electron transfer reactions play an important role in many natural processes. Reactions such as \ndissociation, protonation, and reactions with water and other small molecules often occur in \nbiotransformation. The reaction schemes involving these chemical reactions coupled to the \nelectron transfer can be determined by cyclic voltammetry. Additionally, in \nsitu spectroelectrochemistry can efficiently contribute to the determination of oxidation or \nreduction mechanism. This technique provides information about the electroactive chromophore during \nthe redox process allowing to identification the first reaction intermediates. The final reaction \nproducts were identified by chromatographic techniques. This study represents a key role of TR \nspectroelectrochemistry in the determination of reaction intermediates in the case of \n1,10- phenanthroline derivative substituted by bioactive phenothiazine unit and \ndrug 3- fluorophenmetrazine (2-(3-fluorophenyl)-3-methylmorpholine, 3-FPM). Co pound 3-FPM\nhave recently appeared as the new psychoactive substance in the drug market.\n
Klíčová slova:
IR spectroelectrochemistry; psychoactive substances; oxidation mechanism
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Application of In situ TR Spectroelectrochemical Techniques in Determination of Redox Mechanism of Bioactive Compounds
The electron transfer reactions play an important role in many natural processes. Reactions such as \ndissociation, protonation, and reactions with water and other small molecules often occur in ...
A polarizable reference electrode
Mareček, Vladimír
2023 - anglický
New concept of a reference electrode for electrochemical systems resolves a problem of a poor \npotential stability of refence electrodes based on the distribution of a strongly \nhydrophobic common cation between two immiscible electrolyte solutions (TTTES). The use of a \npolarizable metal electrode instead of a classical reference electrode is demonstrated in \n a modified conventional four-electrode cell with TTTES. A simple battery operated potentiostat \ncontrols the working electrode potential in a three-electrode configuration. The working metal \nelectrode then serves as a polarizable reference organic solvent electrode in a four-electrode \nsystem for the polarization of the water/organic solvent interface.\n\n
Klíčová slova:
reference electrode; liquid/liquid interface; chloride extraction
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
A polarizable reference electrode
New concept of a reference electrode for electrochemical systems resolves a problem of a poor \npotential stability of refence electrodes based on the distribution of a strongly ...
Determination of Selected Natural Psychoactive Substances in Organic Matrices at 3D Printed Electrodes
Choińska-Mlynarczyk, Marta; Šestáková, Ivana; Navrátil, Tomáš
2023 - anglický
Psilocybin and its derivative psilocin are popular psychoactive substances both as experimental\ntreatments in clinical trials and as illicit drugs. Their potential ability to influence the human\nbrain entails the need for a fast, inexpensive, selective, and sensitive method of their\ndetermination. The aim of our study was the development of new 3D-printed electrodes which\nfulfill these demands and are useful for medical, toxicological, and forensic purposes.\nSuccessful development allows determining in real matrices (human plasma and dried\nmushrooms) concentrations of the order of 1 μmol dm-3.\n
Klíčová slova:
natural psychoactive substances; 3D-printed electrodes; psilocin; psilocybin
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Determination of Selected Natural Psychoactive Substances in Organic Matrices at 3D Printed Electrodes
Psilocybin and its derivative psilocin are popular psychoactive substances both as experimental\ntreatments in clinical trials and as illicit drugs. Their potential ability to influence the ...
Ceramic protection of anti-corrosion layers of 3-glycidyloxypropyl-triethoxysilane on steel
Pokorný, P.; Prodanović, N.; Janata, Marek; Brožek, Vlastimil
2023 - anglický
There are various variations on the problem of steel reinforcement bond strength in concrete. Along with geometrical considerations, corrosion performance of steels with varying chemical compositions in interaction with variable chemical compositions of concrete are crucial. One approach is to cover steel surfaces with organosilane compounds, which increases the reinforcement resistance to corrosion in both acidic and alkaline conditions but, on the other hand, may weaken the reinforcement bond strength on concrete. The issue is resolved by intentionally forming a thin-walled, highly adhering corundum layer that is highly porous and impregnated with 3-glycidyloxypropyltriethoxysilane. This procedure also includes testing the adhesion properties between the ceramic and the metal and the cement prior to conducting a corrosion test in a chloride environment.
Klíčová slova:
steel; concrete; ceramics
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Ceramic protection of anti-corrosion layers of 3-glycidyloxypropyl-triethoxysilane on steel
There are various variations on the problem of steel reinforcement bond strength in concrete. Along with geometrical considerations, corrosion performance of steels with varying chemical compositions ...
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
Šimurda, David; Hála, Jindřich
2023 - anglický
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Klíčová slova:
compressor blade cascade; experiment; subsonic flow; optimized profile
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Infants' learning of novel segments is modulated by prosody
Chládková, Kateřina; Podlipský, V.J.; Nudga, Natalia; Paillereau, Nikola; Kynčlová, Kateřina; Šimáčková, Š.
2023 - anglický
Young infants recognize atypical realisations of native-language speech. Later they learn words better from native-accented talkers. However, 6-month-olds preferentially listen to unfamiliar speech. We tested whether the learning of new vowels matches 6-month-olds’ listening preferences, being more effective from nonnative-accented speech. We exposed Czech six-month-olds to delexicalised utterances with consonants replaced by [f] and vowels by 405 tokens sampled from a bimodal [ɛ]-[æ] distribution, a contrast absent from Czech, and with either native or atypical rhythm. Discrimination of [ɛ]-[æ] was then tested in an alternating/non-alternating paradigm. Longer first-look duration to non-alternating than to alternating trials – indicating a learning effect – was found in infants familiarised with the novel contrast in atypical rhythm, such effect was not\ndetected after familiarisation with native rhythm. Six-month-olds thus more effectively exploit distributional information about novel vowels from non-native rhythm, which matches their previously reported preferences for listening to novel over familiar accents.
Klíčová slova:
distributional learning; selective learning; non-native rhythm; vowels; infancy
Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Infants' learning of novel segments is modulated by prosody
Young infants recognize atypical realisations of native-language speech. Later they learn words better from native-accented talkers. However, 6-month-olds preferentially listen to unfamiliar speech. ...
2TDK Railway, profile P18. Datings. Final Report.
Bosák, Pavel; Zupan Hajna, N.; Hercman, H.; Horáček, I.; Kdýr, Šimon; Kogovšek, B.
2023 - anglický
Samples for datings were taken in the railway construction (2TDK) near village of Divača, Classical Karst on October 12, 2021: (1) vertebrate bones in cave 2TDK – 002 at the profile P18, cave entrance appeared during the construction operations on cleaned karst surface in a wall of karst depression. Samples of mammal bones and gastropods were collected in situ on cave bottom, and (2) pieces of speleothems occurring in non in situ position on artificially planated surface near the cave opening were collected. U-series: no numerical date was obtained as geochemistry of sample indicate open system, probably due to recrystallization of sample in soil cover. Paleomagnetism: The transition of N- and R-polarized samples cannot be identified more precisely as U-series radiometric dating yielded no numerical results. The transition easily can represent Brunhes/Matuyama boundary (at 773 ka) as well as any of older such transitions (e. g., base of Jaramillo, base of Olduvai). In any case the speleothem grew in a closed cave space with roof, probably as flowstone (inclusion of red soils above the base) and later as baldachin on eroded allogenic fill of the paleocave. Vertebrate paleontology: bone remains of small and larger vertebrates represent subrecent to Holocene species. Sorex alpinus represents the species quite rare in fossil record, but recetly limited to variegated woodland habitats with high surface humidity. A chamois Rupicapra rupicapra represents a resident species present in Slovenia throughout all stages of a glacial cycle, recently restricted to mountain habitats.
Klíčová slova:
Divača Karst; unroofed cave; speleothem; U-Th dating; paleomagnetism; zoopaleontology
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
2TDK Railway, profile P18. Datings. Final Report.
Samples for datings were taken in the railway construction (2TDK) near village of Divača, Classical Karst on October 12, 2021: (1) vertebrate bones in cave 2TDK – 002 at the profile P18, cave entrance ...
Room temperature ethanol detection using carbon materials
Kočí, Michal
2023 - anglický
Allotropic forms of carbon, in particular graphene oxide (GO) or nanocrystalline diamond (NCD), attracted the attention of many research groups due to their unique electronic structures and extraordinary physical and chemical properties, preferable for many different applications, including sensor devices. This work focuses on responses of various sensing layers (NCD with hydrogen termination (H-NCD), graphene oxide (GO), reduced graphene oxide (rGO), thiol-functionalized graphene oxide (GO-SH) and their hybrid structures to ethanol vapor with concentrations up to 100 ppm in synthetic air at room temperature. The measured parameters of the tested sensors, especially stability, reproducibility and regeneration, are compared and critically evaluated. The high sensitivity of tested sensors achieved at room temperature makes them very promising for monitoring ethanol vapor as well as other volatile substances (e.g., isopropyl-alcohol or acetone).
Klíčová slova:
gas sensor; nanocrystalline diamond (NCD); graphene oxide (GO); reduced graphene oxide (rGO); thiol-functionalized graphene oxide (GO-SH)
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Room temperature ethanol detection using carbon materials
Allotropic forms of carbon, in particular graphene oxide (GO) or nanocrystalline diamond (NCD), attracted the attention of many research groups due to their unique electronic structures and ...
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