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Electroanalysis with phthalocyanine modified HOPG electrodes
Mansfeldová, Věra ; Janda, Pavel
In this papers we presented modification of highly oriented pyrolitic graphite (HOPG) by two different phthalocyanine (Pc) derivatives and two different deposition techniques. We have investigated electrode modified by fullerene-derived phthalocyanine and cobalt tetraneopentoxyphthalocyanine (CoTNPc) to consider how different modification procedure-electrodeposition and drop evaporation and composition of phthalocyanine influences detection of model compound, L-cysteine.
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Electrochemical and spectrometric study of FOX-7 in aprotic solvents
Šimková, Ludmila ; Ludvík, Jiří ; Klíma, Jiří
2,2-Dinitroethene-1,1-diamine (FOX-7) is a recently developed and broadly tested energetic material with high efficiency and low sensitivity. Generally, explosion is based on thermally initiated chain of intramolecular redox reactions. Recently it has been found that electrochemical reduction in aqueous solutions is also able to provoke the chain of follow-up processes leading to total decomposition of the parent substance yielding gaseous products analogously like during explosion. Similarly, results from reductive electrolysis of FOX-7 in aprotic solvents show analogous course of degradation. The first transferred electron activates the molecule and initiated the formation of colored radical intermediates that have been spectroscopically characterized
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Voltammetric determination of anticancer drug flutamide at screen-printed carbon electrodes
Vyskočil, V. ; Navrátil, Tomáš ; Barek, J.
Flutamide, 4-nitro-3-trifluoromethyl-isobutylanilide, is the active component of a synthetic nonsteroidal antiandrogen drug, which is commonly used in the treatment of advanced prostate cancer. In this contribution, optimum conditions have been found vor voltammetric determination of flutamide by DC voltammetry (DCV) and differential pulse voltammetry (DPV) at screen-printed carbon electrodes (SPCEs). Under optimum conditions (Britton-Robinson buffer pH 7.0 - methanol (9:1)), linear calibration curves were measure with limits of quantification 6x10(-7) molL(-1) and 8x10(-7) molL(-1) for DCV at SPCEs, respectively. The newly developed methods were successfully applied to the determination of the drug in pharmaceutical formulation Apo-Flutamide (Eulexin tablets).
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Bioimpedance methods to measure somatometric and volumetric changes
Petr, M. ; Kohlíková, E. ; Navrátil, Tomáš
Assessment of human body composition has stimulated the need for an understanding of available methodologies of estimating fat free mass and percent body fat. In our study, we found statistical significant changes of body composition evaluated by multi-frequency bioelectrical analysis in a group of athletes following creatine supplementation. These results are consistent with literature i.e. supplemented creatine effects osmolality of cell´s membranes which leads to increased intracellular water retention. Multi-frequency BIA can be considered to be an accurate and sensitive method for assessment of human body composition.
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Evaluating the accuracy of continuous glucose monitoring by the patient through continuous glucose error grid analysis
Honsová, Š. ; Navrátil, Tomáš
The aim of the study is to compare the difference between the accuracy declared by the producer of continuous glucose determination using the MiniMed Paradigm REAL-Time system with the results achieved by patients in real life. The glucose sensor evaluates the catalytic transformation of glucose (enzyme glucose dehydrogenase) to hydrogen peroxide, the concentration of which is electrochemically evaluated. The accuracy of measurements was determined by Clarke Error Grid Analysis. It can be concluded that in normal glyceamia (4.4 to 10.0 mmol/l) the measurements realized by the parients are more accurate that it is supposed by the producer, opposite to the cases of hypoglycaemia or hyperglycaemia.
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Transport of divalent cations across the gel supported phospholipid membranes
Navrátil, Tomáš ; Šestáková, Ivana ; Mareček, Vladimír
This contribution deals with elucidation of principles of transporting processes of heavy metals (mainly lead, cadmium) across the biological membranes. The real membranes were for purposes of described experiments, replaced by model membranes, which were composed of phospholipid bilayers. Two different phorpholipids (1,2-dipalmitoyl-sn-glycero-3-phosphocholine and the mixture of phospholipids obtained from soybeans (under commercial name Asolectin)) were used as the building elements for the formation of these membranes on the surface of the constructed gel electrode. The registered transporting processes have been characterized using voltammetry, and electrochemical impendance spectrometry (EIS). The impact of some parameters on these systems and processes was investigated.
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