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Electrochemical Techniques in Monitoring of Nervous System Drugs
Choińska-Mlynarczyk, Marta; Hrdlička, Vojtěch; Skopalová, J.; Šelešovská, R.; Kolivoška, Viliam; Navrátil, Tomáš
2022 - English
Drugs of the nervous system (ATC group N) belong generally to the most commonly (mis)used substances worldwide. Their determination and monitoring of these drugs and their metabolites in various body fluids or environmental matrices represent a challenge for analytical chemists. Our research is focused on the application of electrochemical methods in the monitoring of the most frequently prescribed and the newly introduced nervous system drugs of precisely specified structures and/or of defined properties. For toxicological and pharmacokinetic reasons, emphasis has been placed on investigating the reaction mechanisms of their metabolite formation. New or alternative to commonly used electroanalytical methods applicable for monitoring and characterization of target compounds in their pure state, in body fluids, wastewaters, and other environmental matrices, has been developed. To improve the chemometric parameters and sensing characteristics, attention was paid to the construction of new electrochemical sensors, detectors (e.g. screen-printed, 3D printed), or cells, based on (modified/unmodified) traditional or nontraditional materials, preferably usable at the point-of-care.
Keywords:
nervous system drugs; active pharmaceutical ingredient; metabolites; electrochemistry
Available on request at various institutes of the ASCR
Electrochemical Techniques in Monitoring of Nervous System Drugs
Drugs of the nervous system (ATC group N) belong generally to the most commonly (mis)used substances worldwide. Their determination and monitoring of these drugs and their metabolites in various body ...
(Spektro) Elektrochemická studie derivátů cibalackrotu – potenciální chromofory pro singletové štěpení
Šimková, Ludmila; Lušpai, Karol; Klíma, Jiří; Ludvík, Jiří
2022 - Czech
V posledních letech je věnovaná velká pozornost zvýšení účinnosti solárních článků. Jednou z uvažovaných možností je využití fotofyzikálního procesu označovaného jako singlet fission (SF), neboli štěpení singletu 1. Jedná se o děj, v jehož průběhu jedna molekula v excitovaném singletovém stavu předá polovinu své energie druhé, sousední molekule v základním stavu za vzniku dvou tripletově excitovaných molekul 2. Takto se po separaci nábojů mohou generovat z jednoho fotonu dva elektrony, což představuje nadějný směr pro zvýšení účinnosti solárních článků. Tento efekt je laboratorně prokázán i teoreticky ověřen, ale k uvedení do praxe dosud chybí vhodný, dostatečně stabilní materiál. V současné době probíhá syntéza a studium několik typů chromoforů pro SF. Slibnými kandidáty se ukázaly velké aromatické uhlovodíky biradikaloidů například substituované difenylisobenzofurany 3 a cibalackroty, sloučeniny blízké indigu, kterým jsme se nově začali věnovat.\nMolekula indiga je považována za hlavní příklad biradikáloidu s vhodnou singletovou a tripletovou excitační energií pro singletové štěpení 2. Jako kandidát na SF je ale vyřazen kvůli rychlému podléhání fotochemické cis-trans izomeraci dvojné vazby a přenosu protonu z dusíku na kyslík. Naopak průmyslově užívané barvivo cibalackrot odvozené od indiga by mohlo představovat vhodného kandidáta pro SF. Stejně jako indigo splňuje energetické podmínky pro SF a navíc má obě zmíněné deaktivační cesty blokovány.\nPro případné použití nového chromoforu v solárních článcích je nezbytné studium redoxních vlastností v souvislosti s UV-vis a EPR spektry. S využitím skutečnosti, že určitý substituent má malý vliv na elektronové excitační energie a pravděpodobně další vlastnosti relevantní pro štěpení singletu, vybrali jsme řadu derivátů cibalackrotu syntetizovaných pro případné využití v praktických aplikacích singletového štěpeni a lišících se strukturními aspekty (Obr. 1) s cílem nalézt pravidlo pro návrh nejslibnějšího chromoforu pro SF. Svoji pozornost jsme proto zaměřili nejen na studium oxidace a redukce ale zapojili jsme i in situ UV-vis a EPR spektroelektrochemické metody za účelem charakterizace struktury a stability elektrochemicky generovaných aktivovaných (vč. radikálových) částic. Recently, substantial attention has been paid to the search for suitable chromophores for singlet fission. This photophysical effect promises to increase the maximum of theoretical efficiency of solar cells. One type of candidates are derivatives of cibalackrot. Redox properties are critical for their use. Our electrochemical work is focused on the study of oxidation and reduction of a series of substituted cibalackrot derivatives using classic voltammetric techniques and their combination with in situ UV-vis and EPR spectroscopy. The results show the reversible formation of the radical anion (cation) in the first reduction (oxidation) step enabling determination of ´´electrochemical´´ HOMO-LUMO gap.
Keywords:
Cibalackrot; Singlet fission; Reduction; EPR; Spectroelectrochemistry
Available on request at various institutes of the ASCR
(Spektro) Elektrochemická studie derivátů cibalackrotu – potenciální chromofory pro singletové štěpení
V posledních letech je věnovaná velká pozornost zvýšení účinnosti solárních článků. Jednou z uvažovaných možností je využití fotofyzikálního procesu označovaného jako singlet fission (SF), neboli ...
Redoxní vlastnosti konjugovaných derivátů fosfolů – elektrochemická studie
Koláčná, Lucie; Polák, P.; Tobrman, T.; Ludvík, Jiří
2022 - Czech
Fosfoly a jejich deriváty jsou často využívány jako stavební kameny v π-konjugovaných systémech. Nacházejí uplatnění v katalýze, bio-anoganické i materiálové chemii, např. jako OLED (Organic light-emitting diode – světlo vyzařující organické diody), OPV (Organic Photovoltaics – organické fotovoltaické články), OFET (Organic field-effect transistor – organické tranzistory řízené elektrickým polem), NLO (nelineární optické přístroje), luminiscenční materiály, polovodiče, tekuté krystaly i molekulární stroje. \nRedoxní vlastnosti studovaných molekul byly sledovány v nevodném prostředí acetonitrilu (AN) na různých elektrodách pomocí oxidace a redukce. Vyhodnocení oxidačních a redukčních potenciálů a jejich interpretace, jejich posunů a rozdílů umožnilo určení tzv. ´´elektrochemického´´ HOMO-LUMO gap, studium podílu substituentů na celkových redoxních vlastnostech studovaných látek i ovlivnění planarity molekuly a míry delokalizace elektronů. The study describes pentasubstituted phospholes with a π-conjugated arms in positions 2 and 5 of the phosphole ring. According to the expectations, substituents with electron-donating groups led to lower oxidation potentials, the presence of electron-withdrawing groups shifts the reduction potential to less negative values. Because all studied phospholes have multiple substituents of both types, their resulting potentials represent the sum of their influences. Moreover, since many of the studied compounds have two redox centers (phosphole moiety itself and the pi-conjugated arm), their locations were determined and intramolecular interactions were followed, because substituents which can be conjugated with the π-system of phosphole are able to extend the delocalized π-system resulting in stabilization of primary redox intermediates. Chemical modification of phospholes using various combinations of substituents can set the desired electrochemical properties of studied molecules.
Keywords:
phosphole; conjugation; electrochemical rteduction and oxidation; polarography
Available on request at various institutes of the ASCR
Redoxní vlastnosti konjugovaných derivátů fosfolů – elektrochemická studie
Fosfoly a jejich deriváty jsou často využívány jako stavební kameny v π-konjugovaných systémech. Nacházejí uplatnění v katalýze, bio-anoganické i materiálové chemii, např. jako OLED (Organic ...
Electrochemical Characterization of Self-Assembled Monolayers Containing Redox Switching Element
Nováková Lachmanová, Štěpánka; Kocábová, Jana; Vavrek, František; Sebechlebská, Táňa; Šebera, Jakub; Kolivoška, Viliam; Lukášek, J.; Balzer, N.; Valášek, M.; Hromadová, Magdaléna
2022 - English
Adsorption properties of molecules containing [Ru(terpy)2]2+ and [Os(terpy)2]2+ redox switching element connected to the electrode surface by tripodal thiolate anchoring groups have been studied together with their charge transfer properties in the adsorbed form. STM-based current-voltage measurements confirmed that the conductance of self-assembled monolayer containing [Os(terpy)2]2+ redox switching element is lower than that containing [Ru(terpy)2]2+ element. This observation agrees with previously observed differences in the electron transfer rate constants of these molecules in their adsorbed state.
Keywords:
[Ru(terpy)2]2+; [Os(terpy)2]2+; Tripodal Anchor; Self-Assembled Monolayer; Electrochemical Impedance Spectroscopy
Available on request at various institutes of the ASCR
Electrochemical Characterization of Self-Assembled Monolayers Containing Redox Switching Element
Adsorption properties of molecules containing [Ru(terpy)2]2+ and [Os(terpy)2]2+ redox switching element connected to the electrode surface by tripodal thiolate anchoring groups have been studied ...
Voltammetric Determination of Psilocin and Psilocybin at Carbon-fiber PLA Electrode
Choińska-Mlynarczyk, Marta; Navrátil, Tomáš
2022 - English
Psilocin and psilocybin are two neuroactive drugs. They can be used in experimental treatment in psychiatry, moreover, also as illicit drugs to achieve hallucinations and relaxation. Easy access to these two alkaloids indicates that their monitoring in the environment and the body fluids is necessary. Electrochemistry offers fast, simple, and easy methods of their determination using laboratory-manufactured electrodes from 3D printed carbon-fiber polylactic materials. This technique of electrode fabrication can be characterized by many benefits, e.g., desired shape or diameter of the electrode, well-developed voltammetric signals, and low background currents.
Keywords:
psilocin; psilocybin; determination; voltammetry; 3D printed electrodes
Available on request at various institutes of the ASCR
Voltammetric Determination of Psilocin and Psilocybin at Carbon-fiber PLA Electrode
Psilocin and psilocybin are two neuroactive drugs. They can be used in experimental treatment in psychiatry, moreover, also as illicit drugs to achieve hallucinations and relaxation. Easy access to ...
Analysis of the Hydrated ions Clusters Impact on the Liquid/Liquid Interface
Mareček, Vladimír; Samec, Zdeněk; Trojánek, Antonín
2022 - English
Open circuit potential (OCP) measurements of the partition of tetrapentylammonium chloride (TPeACl) at the water/1,2-dichloroethane (DCE) interface reveal two remarkable processes. The first one is characterized by a decay of the OCP from its expected equilibrium value. This process has been ascribed to the extraction of the salt driven by its accumulation in the hydrated salt clusters in the DCE phase. The second process is characterized by the short-term potential spikes overlapping the long-term OCP records. These spikes are assumed to be associated with the collision and fusion of the hydrated salt clusters produced by the former process with the water/DCE interface.
Keywords:
Water/1,2-dichloroethane interface; Salt partition; Open circuit potential
Available on request at various institutes of the ASCR
Analysis of the Hydrated ions Clusters Impact on the Liquid/Liquid Interface
Open circuit potential (OCP) measurements of the partition of tetrapentylammonium chloride (TPeACl) at the water/1,2-dichloroethane (DCE) interface reveal two remarkable processes. The first one is ...
Manufacture of 3D Printed Microfluidic Channels and Their Characterization by Impedance Spectroscopy and Optical Microscopy Measurements
Štěrba, O.; Vaněčková, Eva; Choińska-Mlynarczyk, Marta; Navrátil, Tomáš; Kolivoška, Viliam
2022 - English
Fused deposition modeling 3D printing employing high-resolution extrusion nozzles and specialized manufacturing protocols have recently attracted attention as an inexpensive tool to create microfluidic devices. In this work, we have applied such an approach to create measurement cells with integrated microchannels of systematically varied dimensions. The real width of channels was inspected by two techniques, namely (A) impedance spectroscopy employing an aqueous sensing electrolyte and (B) optical microscopic imaging of silicone imprints hardened in the interior of printed structures. Both techniques have demonstrated that fused deposition modeling 3D printing enables precise manufacturing of channels with truly microfluidic dimensions.
Keywords:
Fused deposition modeling 3D printing; Lab-on-a-chip devices; Microfluidic channels; Impedance spectroscopy; Optical microscopy
Available on request at various institutes of the ASCR
Manufacture of 3D Printed Microfluidic Channels and Their Characterization by Impedance Spectroscopy and Optical Microscopy Measurements
Fused deposition modeling 3D printing employing high-resolution extrusion nozzles and specialized manufacturing protocols have recently attracted attention as an inexpensive tool to create ...
Mercury Film Screen-Printed Electrodes
Josypčuk, Bohdan; Šestáková, Ivana; Tvorynska, Sofiia
2022 - English
Mercury film screen-printed electrodes (MF-SPEs) were designed, prepared and tested for the first time as perspective representatives among SPEs that allow measuring at high negative potentials. For this purpose, the precise electrochemical (coulometric) preparation procedure for mercury deposition at the working electrode surface of the commercial silver-SPE was developed and a universal method of preparing MF-electrodes from different metal-SPEs was described. An optimal electrolyzer construction for the mercury deposition, electrolyte composition, electrolysis potential, and an activation of electrode surfaces were proposed. Determination of the zinc content in food supplement tablets was used for the MF-SPEs practical testing.
Keywords:
flow analysis; mercury film; screen-printed electrodes; electrochemistry
Available on request at various institutes of the ASCR
Mercury Film Screen-Printed Electrodes
Mercury film screen-printed electrodes (MF-SPEs) were designed, prepared and tested for the first time as perspective representatives among SPEs that allow measuring at high negative potentials. For ...
Spectroelectrochemistry of 1,10-phenantrolines Substituted by Pyrrolidine and Phenothiazine Redox-active Units
Sokolová, Romana; Wantulok, J.; Fiedler, Jan; Nycz, J.; Degano, I.
2022 - English
Compounds based on 1,10-phenanthroline (Phen) and their complexes are used in many fields, such as a stabilizing agent in the synthesis of nanoparticles, catalysts in homogeneous catalysis and as a semiconductor in organic light-emitting diodes (OLED) due to their coordination abilities. In this work, 1,10-phenanthrolines functionalized by pyrrolidine and phenothiazine units were studied by electrochemical methods. Cyclic voltammetry resulted in several oxidation and reduction voltammetric peaks. Structure-activity relationship was investigated using in situ spectroeletrochemistry, spectrophotometry, infrared spectroscopy and chromatography.
Keywords:
1,10-phenanthroline; Electrochemistry; Oxidation mechanism; Reduction mechanism
Available on request at various institutes of the ASCR
Spectroelectrochemistry of 1,10-phenantrolines Substituted by Pyrrolidine and Phenothiazine Redox-active Units
Compounds based on 1,10-phenanthroline (Phen) and their complexes are used in many fields, such as a stabilizing agent in the synthesis of nanoparticles, catalysts in homogeneous catalysis and as a ...
EPR-elektrochemická studie redukčního mechanismu konjugátů pyrenu a cyklobutenu
Koláčná, Lucie; Polák, P.; Klíma, Jiří; Tobrman, T.; Ludvík, Jiří
2021 - Czech
Čistě organické konjugované systémy nacházejí v současné době široké uplatnění\nv materiálové chemiiý. Jsou často využívané také pro přípravu organických polovodičů, na\nkteré je zaměřen náš projekt. ´´Green smart molecules´´ jsou biodegradovatelné látky, které\nneobsahují žádné kovy. Velkou výhodou je možnost úpravy jejich vlastností změnou struktury\npomocí prosté chemické modifikace. Reduction mechanism of pyrene-cyclobutene conjugates were studied electrochemically and\nspectro-electrochemically. Analysis and interpretation of spectro-electrochemical data of\nconjugates revealed intramolecular communication of electrons and enabled determination of\nredox mechanism of conjugates. This knowledge is fundamental for tuning the required redox\nproperties of molecules just by chemical modification. Studied molecules represent promising\nmaterial for organic semiconductor materials.
Keywords:
Pyrene; Electrochemical reduction; Cyclobutene
Available on request at various institutes of the ASCR
EPR-elektrochemická studie redukčního mechanismu konjugátů pyrenu a cyklobutenu
Čistě organické konjugované systémy nacházejí v současné době široké uplatnění\nv materiálové chemiiý. Jsou často využívané také pro přípravu organických polovodičů, na\nkteré je zaměřen náš projekt. ...
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