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Sorption of radionuclid 85Sr to soils from area nuclear power plant Temelín
Reidingerová, Markéta ; Nesměrák, Karel (advisor) ; Rychlovský, Petr (referee)
This thesis is focused on the study of sorption of radionuclide 85 Sr in soil collected in the area of a nuclear power plant Temelín. A single-batch method experiment was used when a solution of radionuclide 85 Sr of known activity was added to the soil. The experiments focussed on the influence of pH with the size of the sorption and the influence of the time of the contact of the solution with the sorption. During the experiment with the value of pH closest to the pH of underground water from the nuclear power plant Temelín, the sorption of soil was somewhere between 31 to 44 %. When the time influence on the sorption was examined, radionuclide 85 Sr was sorbed very quickly. For the comparison of the sorption size in connection with the time, for which it was chosen 120 minutes, the sorption was almost constant, reaching 40 to 48 %. Key words Radioactivity, radionuclide 85 Sr, sorption, nuclear power plant Temelín
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Speciation analysis of chromium in particulate matter of urban dust
Rybínová, Marcela ; Rychlovský, Petr (advisor) ; Hraníček, Jakub (referee)
Anion-exchange chromatography with inductively coupled plasma - atomic emission spectrometry (ICP-AES) has been used for the speciation of chromium (Cr). Chromium speciation has attracted attention because of the different toxicity, Cr(III) is relatively non-toxic and Cr(VI) has been classified as a human carcinogen. The aim of the present study was to develop simple method for the speciation analysis of Cr (Cr(III) and Cr(VI)) in particulate matter of urban dust. A combination of 2% KOH + 3% Na2CO3 has been chosen as the optimal reagent for the extraction of chromium from particular matter. It was found that there was no conversion of Cr(VI) into Cr(III). The effect of separation parameters such as acidity of mobile phase was also studied. The detection limit for Cr(VI) was about 12 ng.ml-1 . Results for the determination of Cr(VI) were confirmed by the analysis of standard reference material (BCR CRM 545, Cr(VI) in welding dust loaded on a filter) with good agreement between certified (40,16 ± 0,60 μg.g-1 ) and found (37,83 ± 1,14 μg.g-1 ) values.
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Possibilities of electrochemical generation of volatile compound of thallium
Marschner, Karel ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
The possibilities of electrochemical generation of volatile thallium hydride have been studied in this work. A thin-layer electrolytic cell with minimal volume of cathode chamber has been employed. All experiments have been employed in electrochemical continuous flow generation. An electrochemical hydride generation technique was developed to improve the determination of analytes by atomic spectrometry. Effect of various experimental conditions such as kind of cathode material, type and concentration of electrolyte, amount of generation current and flow rate of carrier gas on the absorption signal was examined. Under the optimal values of previously mentioned parameters, the low sensitivity of thallium determination was achieved. So the experimental setup is not suitable for determination of low concentration of thallium in specimens. Keywords Atomic absorption spectrometry, electrochemical generation of volatile compounds, hydrides, thallium, electrolytic flow cell, optimization
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Determination of Procaine by Flow Injection and Sequential Injection Analysis with Spectrophotometric Determination
Tomanová, Marie ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
This diploma thesis is focused to the determination of procaine using flow injection and sequential injection analysis coupled with spectrophotometric detection. This determination is based on the reaction of procaine with a colouring agent, 1,2-naphthoquinone-4-sulfonic acid. An orange coloured product is formed, which is determined spectrophotometrically at the wavelength 484 nm. The high of the absorption signal of the product is directly proportional to the concentration of procaine. The aim of this work was to optimize the parameters of both methods of flow analysis so that the limit concentration of procaine can be as low as possible and at the same time, high sensibility is achieved. The next step was to apply these methods on the determination of procaine in real samples. It was found that in flow injection analysis, the absorbance of procaine hydrochloride obeys Beer's law for concentrations from 2.5 to 120 µg/ml. The linear regression equation of calibration graph was y = 0.0059x - 0.0051, with a linear regression correlation coefficient 0.9993. Limit of detection was 0.72 µg/ml. Effects of standing time (stopped-flow), flow rate, concentration of colouring agent, pH and the volume of the sample loop have been examined and optimized. It was also found that in sequential injection...
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Study of Factors Influencing the Teduction of Rhenistane
Burešová, Helena ; Nesměrák, Karel (advisor) ; Rychlovský, Petr (referee)
The aim of the bachelor thesis was to study the influence of conditions on the reduction of ammonium perrhenate by selected reduction agents. The amount of reduced perrhenate was followed by differential pulse voltammetry (as the decrease of the height of DPV peak). The percentage of reduced perrhenate was expressed as a function of molar ratio of the reduction agent to perrhenate. The following four agents were employed: sodium borohydride, hydroxylamine hydrochloride, hydrazine hydrochloride, and ascorbic acid. An amount of 97.8% of rhenium reduced was achieved by 0.9-fold of molar excess of sodium borohydride in 2 mol dm-3 perchlorid acid. The threefold molar excess of hydroxylamine hydrochloride reduced rhenium by 85% (in medium with pH = 8.5). The threefold molar excess of hydazine hydrochloride reduced rhenium by 68% (in medium with pH = 5.0). Ascorbic acid was the last studied reduction agent; its threefold molar excess reduced rhenium by 98.7%.
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Identification of polyphenolic compounds in plant extracts
Rýdlová, Iveta ; Rychlovský, Petr (advisor) ; Hraníček, Jakub (referee)
Thesis "Identification of selected polyphenols in extracts of medicinal plants" is divided into two parts. The first part is devoted to describing a general division polyphenolic compounds, their antioxidant activity and lists of the methods which are used for the analysis of these substances. The second part deals with the identification of these selected compounds using the RP - HPLC method with UV detection-DAD, and then with the tandem mass spectrometer with a triple quadrupole. The method was optimized, in this method was used gradient elution with 10-90% acetonitrile, 0,1% formic acid and deionized water. Analysis time was 38 minutes. Elution agents ran from polar to less polar substances. First of all eluted substances which contained the hydroxyl group directly on the benzene ring as e.g. phenolic acids, further eluted aglycones with bound sugar, which provides a higher polarity of the substance (flavanones glycosides), further followed the flavonols without attached saccharide units, at the latest the flavones eluted. This optimized method has proved to be reliable with good repeatability and accuracy for separation of polyphenols. Using the UV spectrometry the stability was measured. Due to the stability the substances proved to be stable compounds where their UV spectra don't change with...
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