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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 (advisor) ; Sokolová, Romana (referee)
The anodically oxidized boron doped diamond electrode was used in this study to investigate the electrochemical behaviour of quinoline and its derivative quinine in the anodic area in the aqueous medium, namely using methods of cyclic voltammetry (CV), square wave voltammetry (SWV) and square wave adsorptive stripping voltammetry (SWAdSV) and to adress their potential in voltammetric analysis. It was found by means of SWV that quinoline exhibits one anodic signal in BR buffer in the range of pH 3.0 - 12.0. Quinine shows one anodic signal in the range pH 2.0 - 5.0 later; at higher pH values other 2 to 4 less distinctive signals are formed, i.e, the mechanism is influenced by the presence of quinuclide ring and functional groups at the quinoline skeleton of quinine. It was proved by cyclic voltammetry that the anodic electrode reaction of quinoline is controlled by diffusion; for quinine the results are rather ambiguous. Using the optimized parameteres of SWV (Estep = 5 mV; f = 40 Hz and A = 50 mV) and media of BR buffer pH 5,0, linear dependence peaks height of quinoline on its concentration in the range of 1∙10-7 to 1∙10-4 mol.l-1 was obtained with limit of detection 3.53∙10-7 mol.l-1 . The concetration dependence of quinine under the same conditions is not linear in the range of 6∙10-7 to 1∙10-4...
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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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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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