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Study of Metabolism of Synthetic Cannabinoids. Electrochemical Properties of JWH-018
Obluková, Michaela ; Sokolová, Romana ; Čabala, R.
In the recent years, many new substances have appeared in the drug market, which are abused for their psychoactive effect. They serve as alternative to classical drugs (heroin, cocaine, ecstasy) due to their legal status. The great concern is the ineffectiveness of the current methods of toxicological screening of biological samples to identify these new compounds. It is essential to know the metabolism pathway of these psychoactive substances for a development of a new efficient method for their detection. This report is devoted to understanding of oxidation and reduction mechanism of JWH-018 and JWH-250 by means of cyclic voltammetry and to identification of their redox products.
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Study of electrochemical behaviour of cinchona alkaloids at boron doped diamond electrode
Brunovská, Veronika ; Schwarzová, Karolina (vedoucí práce) ; Sokolová, Romana (oponent)
V tejto štúdii bola použitá anodicky oxidovaná bórom dopovaná diamantová elektróda (BDD) na zistenie elektrochemických vlastností a možností stanovenia chinolínu a jeho derivátu chinínu v anodickej oblasti vo vodnom prostredí a to využitím metód cyklickej voltampérometrie (CV), square wave voltampérometrie (SWV) a adsorpčnej rozpúšťacej square wave voltampérometrie (SWAdSV). Pomocou SWV bolo zistené, že chinolín poskytoval jeden výrazný signál v BR pufri v rozmedzí pH 3,0 až 12,0. Chinín poskytoval jeden signál v rozmedzí pH 2,0 až 5,0, potom sa s narastajúcou hodnotou pH tento pík vyvíjal v dva až štyri menej výrazne signály, tj. mechanizmus oxidácie je ovplyvnený prítomnosťou chinuklidového kruhu či funkčnými skupinami na chinolinovom skelete v štuktúre chinínu. Pomocou cyklickej votlampérometrie, bolo zistené, že elektródový dej chinolínu je riadený difúziou. V prípade chinínu sa nedá všeobecne odvodiť, či je jeho oxidácia riadená difúziou či adsorpciou. Metóda SWV v prostredí BR pufru s pH 5,0 bola optimalizována pre chinolín a s použitím optimalizovaných parametrov (Estep = 5 mV; f = 40 Hz a A = 50 mV) bola zistená lineárna závislosť výšky píkov prúdu chinolínu na jeho koncentrácii v rozmedzí 1∙10-7 až 1∙10-4 mol.l-1 s limitom detekcie 3,53∙10-7 mol.l-1 . V prípade chinínu v rozmedzí...
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Supported Phospholipid Bilayer at the Conductive Interface
Sokolová, Romana ; Kocábová, Jana ; Kolivoška, Viliam ; Gál, M.
The interactions of ethanol and flavonoid compounds with supported phospholipid bilayer\nwere studied by means of electrochemical methods and scanning probe techniques. The\nstability of a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) phospholipid bilayer\nsupported on different types of conductive substrate was investigated. The relationship\nbetween the method of lipid deposition and the formation of several types of lipid structures\nincluding vesicles, hemimicelles, patches and single bilayers on the interface is discussed.
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Fosfolipidy modifikovaná elektroda ze skelného uhlíku a její využití pro stanovení pesticidů
Švecová, H. ; Sokolová, Romana ; Součková, J. ; Skopalová, J. ; Barták, P.
Lipidové membrány jsou již mnoho let studovány jako modely biomembrán. Formování lipidových membrán na povrchu pevných elektrod poprvé popsali Tien a Salamon 1. Od té doby byly použity jako substráty pro lipidové vrstvy různé materiály jako např. stříbro 2, zlato 3, rtuť 4 nebo skelný uhlík 5. Lipidový film na povrchu elektrody je schopen akumulovat organické molekuly v závislosti na jejich náboji a na jejich hydrofilním respektive hydrofobním charakteru. Je známé, že mnoho organických látek, jako jsou pesticidy, léčiva a jiné farmakologicky významné látky, interagují s fosfolipidovou vrstvou a mastnými kyselinami v membráně a mohou být silně akumulovány v lipidové tkáni.
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Oxidation Mechanism of Rhamnetin, a Bioflavonoid Compound
Ramešová, Šárka ; Sokolová, Romana ; Degano, I.
The natural flavonoid rhamnetin (2-(3,4-dihydroxyfenyl)-3,5-dihydroxy-7-methoxychromen-4-one) is important bioactive compound. Rhamnetin was studied in aqueous solution by electrochemical methods. The oxidation mechanism proceeds in sequential steps, which correspond to the hydroxyl oxidation of groups in the three aromatic rings. The study is based on in situ spectroelectrochemistry and identification of products by HPLC-DAD and HPLC–ESI MS/MS.
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Reduction and Oxidation of Hydroxyquinolines in Acetonitrile and Dimethylsulfoxide
Sokolová, Romana ; Ramešová, Šárka ; Fiedler, Jan ; Kolivoška, Viliam ; Degano, I. ; Gál, M. ; Szala, M. ; Nycz, J. E.
This study is focused on investigation of oxidation and reduction pathways of selected hydroxyquinoline compounds in nonaqueous solutions. The experimentally obtained reduction potentials are reported to well correlate with calculated values of LUMO energies as well as the obtained oxidation potentials are in a good agreement with theoretical HOMO energies. The cyclic voltammetry, in situ UV/Vis spectroelectrochemistry and in situ IR spectroelectrochemistry confirmed that the oxidation mechanism is complicated. Oxidation unexpectedly proceeds together with protonation of the starting compound. This behaviour was found for all studied compounds, hydroxyquinoline carboxylic acids and also for compounds, where a methyl group is present instead of carboxylic group.
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Comparison of Techniques for Single-Molecule Conductance Measurements of Expanded Pyridinium Molecules
Lachmanová, Štěpánka ; Hromadová, Magdaléna ; Sokolová, Romana ; Kocábová, Jana ; Gasior, Jindřich ; Mészáros, G. ; Lainé, P. P.
This work is focused on the comparison of two techniques of single-molecule conductance measurements: Scanning Tunneling Microscopy Break Junction technique and Mechanically Controlled Break Junction technique. The structure of studied compound 9-(pyridin-4-yl)benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium allows the formation of the molecular bridge between two gold electrodes, which are connected to a source of the constant voltage in both of the used methods. The differences, advantages and disadvantages of both of the techniques will be discussed. Both techniques provided two values of conductance of studied compound depending on the experimantal conditions.
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