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Determination of heavy metal poisoning antidote 2,3-dimercapto-1-propanesulfonic acid using silver solid amalgam electrode
Choińska-Mlynarczyk, Marta ; Hrdlička, Vojtěch ; Redondo, B. R. ; Barek, J. ; Navrátil, Tomáš
2,3-Dimercapto-1-propane-sulfonic acid (DMPS) was investigated using direct current voltammetry (DCV), differential pulse cathodic stripping voltammetry (DPCSV), differential pulse anodic stripping voltammetry (DPASV), and elimination voltammetry with linear scan (EVLS) at a polished (p-AgSAE)and at a meniscus modified silver solid amalgam electrode (m-AgSAE). EVLS confirmed two consecutive reductions with coupled proton/electron transfer. Voltammetric titrations of DMPS with Pb2+ proved complex formation, with limits of quantification (LOQs) and detection (LODs) 0.3 and 0.1 mu mol L-1 at m-AgSAE and 0.8 and 0.3 mu mol L-1 at p-AgSAE, respectively. Determination of DMPS in commercial drug Dimaval and human urine samples confirmed practical applicability of the developed method.
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Oxidation Processes of N-methylguanines
Trnková, L. ; Třísková, I. ; Liška, Alan ; Ludvík, Jiří
The oxidation processes of N-methylguanines were investigated in both experimental and\ntheoretical way. Voltammetric oxidation potentials of guanine and its methyl analogues,\nacquired on polymer pencil graphite electrode (pPeGE), were compared with the HOMO\n(SOMO) energies calculated by density functional (DFT) methods. Our study contributes to\nunderstanding not only the oxidation processes of methylated guanines but also their role in\nepigenetics.
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Differences in Electrochemical Reduction of Mono- and Polynuclear Acylgermanes
Šimková, Ludmila ; Dunlop, David ; Liška, Alan ; Ludvík, Jiří
Recently, titanocene derivatives have been investigated in term of their potential use as\ncytostatics in the treatment of oncological diseases. The potentials for reduction or oxidation of\nindividual substances are one of the key properties which fundamentally affect the cytostatic\nefficiency. Our previous results led us to investigate the redox properties of series of titanocene\ndifluoride and dichloride derivatives. This study is mainly focused on the effect of the\nsubstitution of cyclopentadienyl ring and the halide anion on the redox properties of the\nderivative.
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UV-Vis and IR Spectroelectrocbemistry of Copper Complexes and Bioactive Compounds
Sokolová, Romana ; Obluková, Michaela ; Sýs, M. ; Mikysek, T. ; Wantulok, J. ; Nycz, J. E. ; Degano, I.
The interpretation of the change of absorption spectrum of an oxidized and reduced molecule\nrecorded during the electron transfer is an efficient tool for the determination of oxidation or\nreduction mechanism. This technique provides the information about the electroactive\nchromophore and is performed in two regimes of electrochemical measurement, cyclic\nvoltammetry and chronoamperometry, respectively. This approach was successfully applied to\nstudy the fundamental electrochemical behavior of recently synthesized copper complexes\nproviding biomimetic activity, ofpolyphenolic bioactive compounds, and also for the reduction\nof halogenated phenanthrolines. The identification of redox products was done by\nchromatographic techniques as HPLC-DAD and HPLC-ESI-MS/MS.
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Looking into the Photo-stability of Eosin by Electrochemical Methods
Sabatini, F. ; Sokolová, Romana ; Degano, I.
Eosin Y is a synthetic organic dye belonging to the xanthene family. Its bright and fluorescent\npink hue attracted and intrigued the painters of the 19th century, who experimented eosin as\npigment lake (often called Geranium lake) in their paintings. Nevertheless, eosin coloration is\nas beautiful as unstable, and examples of work of arts with faded hues have been documented.\nEosin is not only photo-sensitive but also pH sensitive, making its study very complex. In this\nwork, the combination of electrochemical and spectroscopic techniques revealed to be effective\nfor correlating the physical evidence of eosin fading with its chemical degradation.
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Electrochemical Characterization of Molecular Conductors Containing Redox Switching Element
Nováková Lachmanová, Štěpánka ; Vavrek, František ; Sebechlebská, Táňa ; Šebera, Jakub ; Kolivoška, Viliam ; Lukášek, J. ; Balzer, N. ; Valášek, M. ; Mayor, M. ; Hromadová, Magdaléna
Electrochemical properties of new molecules containing tripodal anchor and redox switching\nelement have been studied by cyclic voltammetry and DFT quantum mechanical calculations.\nComparison of their redox properties with individual organometallic [Ru(terpy)2]2+t3+ and\n[Os(terpy)2]2+t3+ redox centers shows that covalently bonded tripodal anchor does not\ncompromise the reversibility of a redox process and has no effect on the stability of new\nmolecules. New molecular conductors have smaller HOMO-LUMO gap and both are oxidized\nat only slightly more positive potentials after tripodal substitution making them suitable for the\ndevelopment of molecular conductors with switching abilities.
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Differences in Electrochemical Reduction of Mono- and Polynuclear Acylgermanes
Liška, Alan ; Frühwirt, P. ; Haas, M. ; Ludvík, Jiří ; Gescheidt-Demmer, G.
Ail the studied compounds accept first electron under formation a stable anion radical. The\ncorresponding reduction potentials in aprotic media depend on electronic (inductive,\nmesomeric) properties of the substituents, their number, and position. Here, aromatic acyl group\n(benzoyl group with various substitution on aromatic ring) is the principal substituent. The\nredox properties of presented organoelement compounds with central heteroatom Ge (Si, Sn)\nare controlled by peripheral carbonyl groups (in role of redox centers), their number, and\naromatic ring substitution. The measured first reduction potentials E1 values are found in wide\nrange (> 900 mV) due to the fact that the redox centers are carbony 1 groups connected through\nheteroatom in case of acylgermanes, while for di- and trinuclear derivatives (which are\nmolecules with multiple redox centers) the easiest reducible center is the bridging aromatic unit\ninfluenced by the closest carbonyl groups. Thus, it is possible to distinguish both groups ofnonequivalent\ncarbonyl substituents.
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