|
|
Electrochemical Biosensors Based on Enzymatic Reactor with Amalgam Powder
Josypčuk, Bohdan ; Barek, J. ; Josypčuk, Oksana
Enzymatic reactor based on the powder of silver solid amalgam was suggested as the main part of biosensors in flow systems for the first time. 4-aminothiophenol, glutaraldehyde and enzyme were gradually bonded to the amalgam surface. Large surface of the fine amalgam particles maintains a big quantity of enzyme molecules. Biosensors were tested with enzymes ascorbate oxidase, glucose oxidase, catalase, tyrosinase and laccase. Electrochemical detection of the oxygen concentration change (for the first 3 enzymes) or the quinones concentration (tyrosinase and laccase) in the measured solution was done amperometrically by means of the tubular detector of silver solid amalgam. The current response of each biosensor was optimized with respect to the detection potential, the flow rate of the mobile phase, the injection volume and the enzymatic reactor volume. Under the found optimum conditions, concentration dependence and some statistical parameters of repeated measurements (relative standard deviation (RSD) for the studied enzymes was in the range 0.81 – 2.1 %) were measured. Biosensor with the ascorbate oxidase reactor was used for determination of ascorbic acid in the vitamin tablet Celaskon®. Results of the analysis were in good agreement with the contents of ascorbic acid declared by manufacturer and the RSD of these analyses was 2.0 %.
|
|
| |
|
|
Short Information on Methanol Outbreak in the Czech Republic in the year 2012
Navrátil, Tomáš ; Zakharov, S. ; Pelclová, D. ; Mrázová, K.
This contribution reports briefly on the large methanol outbreak in the Czech Republic (CR) in autumn 2012. The first case was registered in September 2012 in Havířov. The source was unknown at that time, but it was connected with the illegal production and sale of adulterated spirits. More than 130 cases of methanol intoxication have been reported during September 2012 – April 2013. 44 people died, about 1/5 of intoxicated patients have suffered by sequels of intoxication and their number have been increasing. Moreover, the samples of methanol can be found in some illegal stores and in some households up to now.
|
|
| |
|
|
Kontinuální monitoring glukózy pomocí Real Time Sensoru v intersticiální tekutině
Honsová, Š. ; Navrátil, Tomáš
Diabetes mellitus (dále DM) je chronické metabolické onemocnění. V současnosti je v České republice evidováno cca 8 % populace jako diabetici. V roce 2011 to bylo 758 719 DM 2, 55 542 DM 1, 11 121 Sekundární diabetes 1. Člověk bez klinických obtíží má koncentraci glukózy v krvi (glykemie) za fyziologických podmínek v rozmezí hodnot 3,9 − 5,6 mmol/l nalačno a po jídle nižší než 10 mmol/l. Podrobné hodnoty a způsoby stanovení jsou zpracovány v literatuře 2. Kontinuální monitoring glykémie (CGM) je zejména u diabetiků 1. typu základní možností zlepšení stavu a kvality života 3. Pro dobrou kompenzaci si diabetici 1. typu mají měřit glykemii nejméně 4x denně. CGM je založen nejčastěji na elektrochemickém principu, u některých typů senzorů se provádí měření na mikrodialyzačním principu nebo na principu reverzní iontoforézy, na fluorescenčním nebo viskozimetrickém principu, nově na principu Ramanovy spektroskopie 4, 5.
|
|
|
(Strept)avidin-biotin interactions at amalgam electrodes covered by thiol monolayer
Josypčuk, Bohdan ; Mareček, Vladimír ; Yosypchuk, O.
Carboxylic group of 11-mercaptoundecanoic acid (MUA) can be used to creat a peptide bond with species containing amino group, e.g., peptides, and proteins. By the help of EDC-NHS technology, streptavidin or avidin was covalently bonded with MUA-monolayer at a silver solid amalgam electrode. Such prepared electrode was used for detecting biotin and biotinylated albumin in the supporting electrolyte (0.15 M NaCl, 0.05 M TRIS, pH 7.0). Electrochemical impendance spectroscopy was performed for the biosensor response monitored by impedance spectroscopy. Binding of biotin or biotinylated albumin with (strept)avidin a change in the resistance of the sensor in the concentration range of 0.5-20 μg mL-1. Electrochemical regeneration of the amalgam electrode permits simply to renew its surface and to create the new biosensor.
|
|
| |
|
|
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,
|
|
|
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.
|
|
|
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.
|
host ::
RSS.