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Voltammetric Behavior of Folates and Related Substances Using Silver Solid Amalgam Electrode
Bandžuchová, L. ; Šelešovská, R. ; Navrátil, Tomáš ; Chýlková, J.
The possibility of application of silver solid amalgam electrode in voltammetric analysis of compounds with folate structure (folic acid, methotrexate, leucovorin) and substances, which play an important role in its metabolism (riboflavin, hydroxocobalamin) has been investigated. Cyclic voltammetry, DC voltammetry and Elimination voltammetry with linear scan has been used for study of voltammetric behavior of mentioned substances and for elucidation of electrochemical reactions. Differential pulse voltammetry has been applied for development of sensitive methods of determination for investigated electroactive compounds. The proposed methods were successfully applied for real samples analysis. Obtained results have been compared with those achieved using HMDE.
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Continuous Glucose Monitoring by Real Time Sensor in Interstitial Fluid
Honsová, Š. ; Navrátil, Tomáš
The aim of this contribution is to compare the differences between accuracy claimed by the manufacturer in continuous glucose monitoring using the MiniMed Paradigm REAL-Time system with the results obtained in a patient during physical activity. Electrochemical glucose sensor measures the glucose oxidase reaction products. Measurement accuracy was determined using Clarke Error Grid analysis. It can be concluded that in the normal glucose range (4.4 to 10.0 mmol/ l) was more accurate than the measurements given by the manufacturer, in the opposite case; hyperglycemia is less precise than declared.
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DOES ONE MONTH CREATINE SUPPLEMENTATION IMPROVE BLOOD LIPIDS?
Kohlíková, E. ; Petr, M. ; Navrátil, Tomáš ; Heyrovský, Michael ; Přistoupilová, K. ; Přistoupil, T. I.
One month’s administration of creatine (CR) in the dose of 5 g/day to 11 young active sportsmen affected their daily amount of CR excreted into urine, and the levels of cholesterol (CH), of triacylglycerols (TAG), of vitamin B12 and of folates in blood. The probands were divided into 4 groups, according to the amount of CR found in urine, and of folates and vitamin B12 determined in blood. It is possible that added CR might induce individually higher offer of 2C units, released under catalysis of vitamin B12 from HoCySH and serine in enzymatic reaction catalyzed by CBS, and in this way higher offer of cysteine and succinyl-CoA This is the main effect of CR in the group D. Both vitamins influence the ratio between glycine (necessary mainly for CR synthesis, beside other metabolic pathways) and serine. The change of serine into glycine can be realized by THF, under catalysis of serine hydroxymethyltransferase. For the opposite change of glycine into serine the metabolic pathway is catalyzed by folates too, but in more complicated way
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Optimization of a Flow Rate for a Hyphenation of Voltammetry with Electrospray Ionization Mass Spectrometry
Jaklová Dytrtová, Jana ; Jakl, M. ; Norková, Renáta ; Navrátil, Tomáš
The hyphenation of an electrochemical cell prior to mass spectrometer with electrospray ionization allows studying of products and/or of intermediates of electrode reactions. The measurement is realized in a flowing system. The flow rate of the sample markedly influences the MS signal intensity of the product. The calculated optimum value for the electrochemical cell with the sweep volume 0.72 μL is in the range from 0.4 to 0.5 mL h -1 . The experimental optimal value is 0.45 mL h -1 . The optimization of the flow rate has to be provided individually for each product, because the intensity also depends on the rate of the electrode reaction and product stability.
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Assessment of Potential Risk Connected with the Use of Mercury and Mercury Electrodes
Navrátil, Tomáš ; Švancara, I. ; Mrázová, K. ; Nováková, Kateřina ; Chýlková, J. ; Pelclová, D.
This contribution tries to asses critically the danger connected with utilization of mercury in different branches of human activites. The main attention was devoted to electrochemistry, mainly to voltammetry and polarography. However, to other branches were characterized as well: dentistry, in battery production, mining industry, and a few others. The most toxic and contarily almost nontoxic forms of mercury and of its compounds were characterized. Some interesting cases of exposure to mercury, according to the database of the Czech Toxicological Information Centre (TIC) (from years 1995-2011), have been reported,
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Use of Copper Solid Amalgam Electrode for Determination of Triazolic Fungicide Tebuvonazole
Nováková, Kateřina ; Navrátil, Tomáš ; Jaklová Dytrtová, Jana ; Chýlková, J.
With the use newly developed mercury meniscus-modified copper solid amalgam electrode (inner diamter 1.5 mm), the voltammetric behavior of fungicide tebuconazole was researched by differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Applying CV and elimination voltammetry with linear scan (EVLS), the reaction mechanism was investigated. The optimum conditions for DPV determination of this triazolic fungucude were identified in Britton-Robinson buffer/methanol (1:1, v/v) of pH 6.3 DPV with optimized parameters (Ein = +400 mV vs. Ag/AgCl/3M KCl, scan rate 20 mV s-1) was used for determination of determination of tebuconazole in analyzed solutions. Application the prolonged time (60 s), the limit of detection 2.10-7 molL-1. The applicability of the developed method was verified on the analysis of the real soil solution sample.
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Investigation of Complexes of Tebuconazole with Zinc
Jakl, M. ; Norková, Renáta ; Navrátil, Tomáš ; Jaklová Dytrtová, Jana ; Balík, J.
Tebuconazole is one of the most utilized triazole pesticides in agriculture. Its stability is highly affected by complexation with metals. Moreover, it creates more or less stable complexes with essential elements that become unavailable to plants. In the system with overbundant tebuconazole, an inert (very stable) complex with Zn was found. Elimination voltammetry wit linear scan was used for revealing of the electrode processes on the mercury surface. The relatively slow kinetically controlled step in tebuconazole/Zn complex formation indication indicates the great ability of Zn-tebuconazole system to react with more ligans. Therefore, multiligand Zn-tebuconazole complexes with other ligands are expected in the nature.
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