Počet nalezených dokumentů: 466
Publikováno od do

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 ...

Navrátil, Tomáš; Trnková, L.; Hrdlička, Vojtěch; Li, X.
Ústav fyzikální chemie J. Heyrovského, 2024

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 ...

Sokolová, Romana; Jiroušková, Eliška; Degano, I.; Wantulok, J.; Nycz, J.
Ústav fyzikální chemie J. Heyrovského, 2023

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 ...

Mareček, Vladimír
Ústav fyzikální chemie J. Heyrovského, 2023

Elektrochemické studium pH závislých redoxních vlastností komplexů mědi s aza-makrocyklickými ligandy
Koláčná, Lucie; Maďar, M.; Kubíček, V.; Ludvík, Jiří
2023 - český
Molekulární elektronika je progresivní směr moderní materiálové chemie. Zabývá se vývojem\nelektronických prvků na úrovni jedné molekuly. Nejdůmyslnější molekulární elektroniku\nnajdeme v přírodě v podobě metaloenzymů. Jedním ze směrů výzkumu jejich modelů jsou\nkomplexy různě substituovaných azamakrocyklů. Předností těchto molekul je jejich stabilita a\ndobře definovaná syntéza. Investigated Cu(II) complexes are based on plain or cross-bridged cyclam. The\nelectrochemically inactive cyclam was modified by carboxylate, phosphonate, or phenolate\npendant arms. Cu(II) represents the main redox center of the complexes. Modification of the\nligand causes a changed pattern of complex redox response in buffered aqueous solution.\nIrreversible Cu(II) reduction results in complex decomposition to amalgamated copper and\nligand in excess. After Cu(0) electrochemical in situ re-oxidation, copper and ligand are recomplexed.\nComplexes undergo isomerization, accelerated by increasing the temperature. The\ninfluence of pH on complex isomerization and the reversibility of its reduction was described. Klíčová slova: cyclam; Cu(II) complexes; pendant arms Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Elektrochemické studium pH závislých redoxních vlastností komplexů mědi s aza-makrocyklickými ligandy

Molekulární elektronika je progresivní směr moderní materiálové chemie. Zabývá se vývojem\nelektronických prvků na úrovni jedné molekuly. Nejdůmyslnější molekulární elektroniku\nnajdeme v přírodě v ...

Koláčná, Lucie; Maďar, M.; Kubíček, V.; Ludvík, Jiří
Ústav fyzikální chemie J. Heyrovského, 2023

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 ...

Choińska-Mlynarczyk, Marta; Šestáková, Ivana; Navrátil, Tomáš
Ústav fyzikální chemie J. Heyrovského, 2023

An Enzymatic Biosensor with Amperometric Detection in a Flow Injection Analysis for the Determination of L-lactic Acid: Development and Application
Tvorynska, Sofiia; Barek, J.; Josypčuk, Bohdan
2023 - anglický
An amperometric biosensor consisting of an enzymatic mini-reactor (lactate oxidase covalently\nattached to −NH2 functionalized mesoporous silica powder SBA−15 using glutaraldehyde) and\na silver amalgam-based screen-printed electrode acting as a transducer was developed for the\ndetermination of L-lactic acid (LA) in FIA. The detection potential of −0.9 V vs. Ag pseudoreference\nelectrode was applied for cathodic detection of enzymatically consumed oxygen.\nUnder the optimized conditions, the constructed biosensor enabled selective determination of\nLA with a micromolar limit of detection. Importantly, the proposed biosensor represented\nexcellent operational stability after ≥350 measurements. Finally, it was successfully applied to\nreal sample analysis. Klíčová slova: L-lactic acid; Lactate oxidase; Amperometric biosensor; silver amalgam Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
An Enzymatic Biosensor with Amperometric Detection in a Flow Injection Analysis for the Determination of L-lactic Acid: Development and Application

An amperometric biosensor consisting of an enzymatic mini-reactor (lactate oxidase covalently\nattached to −NH2 functionalized mesoporous silica powder SBA−15 using glutaraldehyde) and\na silver ...

Tvorynska, Sofiia; Barek, J.; Josypčuk, Bohdan
Ústav fyzikální chemie J. Heyrovského, 2023

Analytická derivatizace pro identifikaci produktů elektrochemické oxidace fentanylů
Barták, P.; Skopalová, J.; Jerga, R.; Štolbová, D.; Navrátil, Tomáš; Langmaier, Jan
2023 - český
Analytická derivatizace a plynová chromatografie s hmotnostní spektrometrií se osvědčily jako\nvhodné nástroje pro identifikaci oxidačních produktů a řešení reakčního mechanismu\nelektrochemické oxidace fentanylů a dalších opioidů. Provedené experimenty potvrdily\npřítomnost fenylacetaldehydu a N-fenylpropanamidu v roztoku po elektrochemické oxidaci\nfentanylu. V případě sufentanilu byl jako odpovídající aldehydický produkt prokázán thiofen-\n2-ylacetaldehyd a v případě furanylfentanylu byl jako amidický produkt prokázán zcela\nanalogicky 2-furanilid. Analytical derivatization and GC-MS analysis were employed for the identification of main\nproducts from the electrochemical oxidation of fentanyl derivatives. Chemical derivatization\nprovides proof of the chemical reactivity of functional groups in oxidation products and serves\nfor the chemical conversion of target compounds into the second series of derivatives to confirm\nthe identification of particular products. Using the direct GC-MS analysis of oxidation products,\nderivatization of aldehydes with cysteamine and derivatization of amides by acidic hydrolysis\nand subsequent reaction with ethylchloroformiate, phenylacetaldehyde, and Nphenylpropanamide\nwere unambigously identified as oxidation products from fentanyl,\nthiophen-2-ylacetaldehyde, and N-phenylpropanamide from sufentanil, and\nphenylacetaldehyde and 2-furanilid from furanylfentanyl. Klíčová slova: electrochemical oxidation; fentanyl; sufentanil; furanylfentanyl Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Analytická derivatizace pro identifikaci produktů elektrochemické oxidace fentanylů

Analytická derivatizace a plynová chromatografie s hmotnostní spektrometrií se osvědčily jako\nvhodné nástroje pro identifikaci oxidačních produktů a řešení reakčního mechanismu\nelektrochemické ...

Barták, P.; Skopalová, J.; Jerga, R.; Štolbová, D.; Navrátil, Tomáš; Langmaier, Jan
Ústav fyzikální chemie J. Heyrovského, 2023

3D Printed Microfluidic Cell for Spectroelectrochemical Analysis
Šikula, M.; Vaněčková, Eva; Hromadová, Magdaléna; Kolivoška, Viliam
2023 - anglický
Recent advances in fused deposition modeling 3D printing (FDM 3DP) enabled \nthe manufacture of customized spectroelectrochemical (SEC) devices. Despite significant progress, \nreported designs still rely on conventional optical components (windows and cuvettes). In this \nwork, we apply bi-material FDM 3DP combining electrically conductive and optically \ntranslucent filaments to manufacture a fully integrated microfluidic SEC device. Employing cyclic \nvoltammetric measurements with redox probes, we demonstrate that the platform allows SEC sensing of \nreactants, intermediates, and products of charge transfer reactions in an oxygen- free \nenvironment. Developed approaches pave the way for SEC d vices with dramatically\nreduced costs compared to currently available commercial platforms.\n Klíčová slova: spectroelectrochemistry; three-dimensional printing; fused deposition modeling Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
3D Printed Microfluidic Cell for Spectroelectrochemical Analysis

Recent advances in fused deposition modeling 3D printing (FDM 3DP) enabled \nthe manufacture of customized spectroelectrochemical (SEC) devices. Despite significant progress, ...

Šikula, M.; Vaněčková, Eva; Hromadová, Magdaléna; Kolivoška, Viliam
Ústav fyzikální chemie J. Heyrovského, 2023

Electrochemical Properties of Mixed Self-Assembled Monolayers Based on Terpyridine Transition Metal Complexes
Kocábová, Jana; Nováková Lachmanová, Štěpánka; Vavrek, František; Valášek, M.; Hromadová, Magdaléna
2023 - anglický
This work presents the electrochemical characterization of mixed self-assembled monolayers\n(SAMs) of [Os(terpy)2]2+ and terpyridine connected by tripodal anchoring groups to the\npolycrystalline gold bead electrode and provides a comparison with SAM based on\n[Os(terpy)2]2+ tripodal molecules without diluting terpyridine tripodal molecules. It is shown\nthat both arrangements enable reproducible preparation of well-defined compact films. The\nelectron transfer rate constant for mixed SAM was determined from cyclic voltammograms\naccording to Laviron’s analysis and compared with the rate constant obtained previously for\nSAM containing only [Os(terpy)2]2+ tripod. Klíčová slova: transition metal complexes; terpyridine; tripodal anchor Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Electrochemical Properties of Mixed Self-Assembled Monolayers Based on Terpyridine Transition Metal Complexes

This work presents the electrochemical characterization of mixed self-assembled monolayers\n(SAMs) of [Os(terpy)2]2+ and terpyridine connected by tripodal anchoring groups to the\npolycrystalline gold ...

Kocábová, Jana; Nováková Lachmanová, Štěpánka; Vavrek, František; Valášek, M.; Hromadová, Magdaléna
Ústav fyzikální chemie J. Heyrovského, 2023

Elimination Voltammetry with Linear Scan: Advantages and Disadvantages
Navrátil, Tomáš; Trnková, L.; Hrdlička, Vojtěch; Li, X.
2023 - anglický
Elimination voltammetry with linear scan (EVLS) represents an almost traditional\nmathematical method that helps to obtain additional and detailed information about the recorded\nelectrochemical signals and therefore, to better understand the analyzed systems. Although it\nhas been substantially developed and expanded during its existence of more than a quarter of a\ncentury and has found many areas of application, like any other mathematical and experimental\nmethod, it exhibits several advantages and disadvantages. In this contribution, we summarize\nits strengths, weaknesses, opportunities, as well as threats.\n Klíčová slova: elimination voltammetry with linear scan; advantages; disadvantages Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Elimination Voltammetry with Linear Scan: Advantages and Disadvantages

Elimination voltammetry with linear scan (EVLS) represents an almost traditional\nmathematical method that helps to obtain additional and detailed information about the recorded\nelectrochemical ...

Navrátil, Tomáš; Trnková, L.; Hrdlička, Vojtěch; Li, X.
Ústav fyzikální chemie J. Heyrovského, 2023

O službě

NUŠL poskytuje centrální přístup k informacím o šedé literatuře vznikající v ČR v oblastech vědy, výzkumu a vzdělávání. Více informací o šedé literatuře a NUŠL najdete na webu služby.

Vaše náměty a připomínky posílejte na email nusl@techlib.cz

Provozovatel

http://www.techlib.cz

Facebook

Zahraniční báze