National Repository of Grey Literature 38 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The utilization of quartz microbalance for detection of toxic compounds
Králová, Miroslava ; Jelínek, Ivan (advisor) ; Opekar, František (referee)
v angličtině: This work is aimed at the study of sensor response of quartz microbalance towards biologically active substances such as glycerin and toxic substances, namely ethylene glycol, methanol and acetonitrile in liquid phase. These toxic organic compounds are widely used in chemical industry as solvents or anti-freeze components. Glycerin is commonly utilized in cosmetic industry as a moisturizer. As human can easily get into contact with these compounds, they should be easily detectable. If tested senzor proves to be suitable for detecting these substances, it will be possible to follow preliminary results and develop the device for practical industrial usage.
The Titrimetric determination with thermometric detection.
Nohavová, Ivana ; Opekar, František (advisor) ; Coufal, Pavel (referee)
Thermometric detection is one of the less usual methods for the objective titration end- point detection. The temperature change at the reaction between an analyte and a titration reagent is monitored by a thermistor. Break-response to the volume of an added titrant indicates reaching the end point of the titration. Subject of this work is to develop a method for the titrimetric determination of acids and bases with this detection method.
A Capacitive Detector for Determination of Organic Solvents in Water Solutions - the Effect of Inorganic Electrolytes.
Fišarová, Michaela ; Opekar, František (advisor) ; Štulík, Karel (referee)
The effect of inorganic electrolytes on the determination of relative permittivity and concentration of water solutions of 1,4 dioxane was studied in this work. The method used was dielectrimetry, and NaCl, KCl, CsCl and LiCl at various concentrations were tested electrolytes. The interfering effect of these electrolytes was found for concentrations above 0.05 mmol l-1. It was also found that the interfering factor is purely the solution conductivity independent on the ion kind. The measurements were carried out with both the planar and the tubular detection cell having the electrodes insulated from the solution. The cell was connected to the differentiator (the voltage is the analytical signal) or multivibrator (the frequency is the analytical signal). A good agreement between experimental results and the modeled calculation for the detector with differentiator was also obtained.
Capillary electrophoresis with dual optical and contactless conductometric detection.
Kadlecová, Tereza ; Opekar, František (advisor) ; Jelínek, Ivan (referee)
This work deals with dual detection of organic and inorganic analytes after separation by capillary zone electrophoresis. In the first part, two types of hydrodynamic sampling are tested. Standard hydrodynamic sampling most often used in laboratory-made electrophoretic apparatus, based on lifting the vessel with the sample, in which the sampling end of the capillary is immersed, and a new method based on increasing the pressure in the sampling vessel without moving the capillary. This sampling procedure minimizes experimenter activity because it is controlled by software. Experimenter only changes vessel containing the sample solution for one with separation electrolyte. The experimental parameters, the sampling time and pressure, are optimized to achieve maximum separation efficiency and adequate detection sensitivity. In the second part of the work, the developed method is tested for the separation of amino-acids in a biological sample (urine).
Determination of Lithium in Mineral Waters Using Electrophoresis in Short Capillary.
Makrlíková, Anna ; Opekar, František (advisor) ; Tůma, Petr (referee)
The aim of this study was determination of lithium ion concentration in mineral waters "Vincentka" and "Bílinská kyselka" using capillary electrophoresis with contactless conductivity detection. A specialized laboratory-made apparatus designed for separations in short capillaries was first tested for separation of model solution of common inorganic cations and then for analysis of mineral water samples. Lithium ion concentration was determined using method of standard addition. The results obtained were compared with those obtained from atomic absorption and emission spectroscopy; standard addition method as well as the method of calibration graph were used in spectroscopic methods. A good agreement was obtained between experimentally determined concentrations of lithium and those declared in the labels on the mineral water bottles. Keywords Capillary electrophoresis, contactless conductivity detection, mineral waters, lithium, atomic absorption spectroscopy, atomic emission spectroscopy

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