National Repository of Grey Literature 149 records found  beginprevious41 - 50nextend  jump to record: Search took 0.01 seconds. 
Determination of heavy metals in gread tits blood and feathers
Labancová, Katarína ; Hraníček, Jakub (advisor) ; Nováková, Eliška (referee)
CZ Tato bakalářská práce se zabývá analýzou vybraných těžkých kovů (olovo, kadmium, měď, chrom, arsen) ve vzorcích krve a peří sýkor koňader (Parus major) metodou atomové absorpční spektrometrie s elektrotermickou atomizací a technikou generování těkavých sloučenin s detekcí křemenného atomizátoru. Za optimálních podmínek byla sestavena kalibrační závislost a zjistěné základní charakteristiky pro jednotlivé prvky. Klíčová slova Atomová absorpční spektrometrie, elektrotermická atomizace, chemické generovaní, těžké kovy, krev, peří, sýkora
Application of Atomic Absorption Spectrometry for Determination of Selected Elements from Potential Ecological Burden Area
Juránková, Lada ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This work is focused on the determination of selected (chemical) elements (Fe, Mn, Zn, Cr, Na, K, Mg a Ca) in a potential ecological burden area using flame atomic absorption spectrometry as a detection technique. A potential ecological burden is represented by tires which are used as a construction material or as an environment surrounding for growing decorative and consumable plants. Analytes were determined in plant origin samples. Firstly, the samples were dried in a laboratory electric dryer. The weighted amount of a dried sample (approximately 0.2 g) was digested inside a microwave decomposition device with an addition of nitric acid and hydrogen peroxide. An optimization of experimental parameters was done for each of the elements before sample measuring. A burner height was optimized and 8 mm height was chosen as a optimum for most elements. Under the optimum condition basic characteristics were measured for each element separately. These characteristics included limits of detection that were: 0.05; 0.01; 0.08; 0.21; 0.02; 0.01; 0.01; 0.01 mg L-1 for the following elements: Fe, Mn, Zn, Cr, K, Ca, Mg and Na, respectively. The limits of quantification, sensitivity and repeatability were determined for each element as well. A significant attention was paid to the content of zinc in the studied...
Arsenic determination in beer samples and raw materials for its preparation
Švadlenová, Veronika ; Hraníček, Jakub (advisor) ; Jelínek, Ivan (referee)
This thesis describes the optimization of the method for determination of arsenic by the chemical hydride generation coupled with AAS detection in beer samples and raw materials for its preparation. The beer usually contain arsenic at ultratrace level, however, it is necessary to monitor the concentration of this element in the beer. The routinely used method for determination of arsenic is determination by electrothermal atomization. This approach is time consuming, expensive and less sensitive. It has been developer suitable determination of arsenic as a faster and less expensive method. For this method there was optimized the flow rate of argon to 75 ml·min-1, the optimum flow rate for the reagents was 4.0 ml·min-1 and for the sample 5.0 ml·min-1 . 3 % NaBH4 in 0.5 % NaOH was used as the reducing agent for the determination of arsenic, and HCl diluted 1:1 with distilled water was used to acidify the sample. With this parameter LOD was 0.32 μg·l-1 and LOQ 1.05 μg·l-1 . It has been tested the arsenic determination in samples of barley, malt and potable water as beer raw materials. It has been found that the beer matrix is unsuitable for the hydride generation technique due to a stormy reaction in the gas/liquid phase separator. The effect of pretreatment, which is likely to enhance the effect of...
Determination of acetylsalicylic acid by sequential injection analysis with spectrophotometric detection
Vrtalová, Martina ; Hraníček, Jakub (advisor) ; Červený, Václav (referee)
This diploma thesis is focused on the determination of acetylsalicylic acid using two methods of flow analysis; Flow Injection Analysis (FIA) and Sequential Injection Analysis (SIA) with spectrophotometric detection. The principle of determination is based on the acetylsalicylic acid decomposition to give salicylic ion. This ion reacts subsequently with Fe3+ ion in acidic solution leading to colored chelating complex Fe(SAL)+ . The increase of absorbance of this complex in its absorption maximum was used for analytical determination. Sodium salicylate (sodium salt of acetylsalicylic acid) was used as a standard substance. In the first part of this work, experimental arrangement for flow injection analysis was setup. Continuously the optimization of experimental conditions of acetylsalicylic acid determination was performed to obtain the higher sensitivity. Under the optimal conditions the basic characteristics of determination was measured. In the second part of this work, the commercial experimental instrument FIA Lab 3500 was used for determination. Optimization of experimental conditions and basic characteristic of determination by sequential injection analysis was performed as well. Developed methods for determination of acetylsalicylic acid with selected technique were verified by analyzing...
Determination of total iron content in selected food supplements
Štádlerová, Barbora ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
In this bachelor's thesis a comparison of three analytical methods for total iron determination in three different food supplements is described. The examined food supplements are Biovit C60, Hemofin and Aktiferrin Compositum. The three methods used for determination of iron are manganometric titration, atomic absorption spectrometry and sequential injection analysis paired with spectrophotometric detection. Two methods were used to prepare solutions of each supplement - they were dissolved in distilled water and also prepared by microwave decomposition of samples. The microwave decomposition is definitely a more suitable preparation method in this case, considering the composition of each supplement. The least suitable of all three methods mentioned above has to be the manganometric titration due to the composition of the matrix. The calibration curve was used to determine total iron content by atomic absorption spectrometry with flame atomization. The agent used in sequential injection analysis to create a product, which can be detected by UV/VIS spectrophotometry was 1,10-phenantroline. The final product was red with the absorption maximum at 512 nm. The most accurate results were obtained by atomic absorption spectrometry.
Electrochemical generation of tellurium volatile compounds with atomic absorption spectrometry
Labancová, Katarína ; Hraníček, Jakub (advisor) ; Jelínek, Ivan (referee)
EN The present diploma thesis deals with the electrochemical generation of volatile tellurium compounds in connection with atomic absorption spectrometry with the main goal to increase the response of the tellurium signals and thus expand the existing knowledge about this element. Tellurium is one of the heavier elements that forms less stable volatile compounds. The reason for choosing these elements was the fact that its concentration increases mainly in landfills where it is released into the environment, which can have an ecological impact and an impact on human health. In the first step, two types of electrochemical cells were constructed - a thin-film flow electrochemical cell with and without an ion exchange membrane and an apparatus with a flow injection arrangement. The choice of cell types, cathode and anode material and apparatus design was chosen based on a literature research. Attention was paid to the optimization of reaction conditions for electrochemical generation of volatile tellurium compounds, which significantly affect the efficiency of generation using a heated quartz tube atomizer. The optimized parameters were electrolyte concentration, carrier gas volume flow rate, electrolyte volume flow rate and generation current. In the second step, the effect of the temperature of the...
Determination of bismuth using chemical generation volatile compounds technique with AAS detection
Petreňová, Štěpánka ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
EN This bachelor thesis is focused on the optimization method of determination of bismuth using chemical generation volatile compound coupled with AAS detection with quartz tube. As a part of this task carrier gas flow rate, the flow rate of working solutions, the concentration of the working solution and the temperature of the atomizer were optimized. After this, the calibration dependence was measured for samples of bismuth in hydrochloric acid and samples of bismuth in deionized water and the basic characteristics of the methods were established. Last part of this thesis was aimed to study of different interfering elements and compounds such as arsenic, lead, copper, iron, sodium, calcium, sulphate and chloride. Key words Chemical generation, atomic absorption spectrometry, bismuth, flow injection analysis, interferences
Extraction method for losartan determination in pharmaceutical compounds by sequential injection analysis with UV/VIS and fluorimetric detection
Zimmermannová, Jana ; Rychlovský, Petr (advisor) ; Hraníček, Jakub (referee)
The diploma thesis deals with the extraction method for determination of losartan using sequential injection analysis with spectrophotometric and spectrofluorimetric detection. The principle of determination is based on losartan ion-pair formation with the orange II and calmagite dyes in an acid buffer, which is then extracted into a chloroform phase. For the purposes of the analytical determination of losartan, an increase in absorbance and fluorescence emission of the ion-pair extracted into the chloroform in its absorption maximum is detected. Losartan potassium was used as the standard substance. First, the conditions for determination in a static arrangement with UV/VIS detection were verified and the basic optimization parameters of determination were measured and the basic characteristics of the determination were identified in the first part of the thesis. An SIA extraction apparatus was prepared and the control programme for the entire analytical process was created in the other part of the thesis. Then the experimental parameters of the determination were optimized and the basic characteristics for both spectrophotometric and spectrofluorimetric detection were measured. The reliability of the losartan determination using the selected methods was verified by analysing real pharmaceutical...
Comparison of basic analytical characteristics of determination for each species of selenium in the chemical and electrochemical hydride generation of selenium species with AFS detection
Šáriczká, Michaela ; Rychlovský, Petr (advisor) ; Hraníček, Jakub (referee)
This thesis deals with the further development of the technique of generation of volatile compounds as derivatization methods by speciation analysis of selenium compounds. Specifically, this diploma thesis compares technique chemical and electrochemical generation of selected species of selenium (inorganic Se (IV) inorganic Se (VI), selenomethionine (Se- Met), selenocysteine (Se-Cys), methyl-selenocysteine (Met-Se-Cys) and seleno-urea (Se-U)). The achieved basic analytical characteristics are compared of each species in non-column arrangement with atomic fluorescence spectrometry. The effect of pre- reduction/decomposition unit are tested, using the pre-reduction agent KBr and hydrochloric acid at higher temperature and in the presence of UV radiation. Keywords Selenium, speciation analysis, chemical hydride generation, electrochemical hydride generation, atomic fluorescence spectrometry
Determination of vitamin B12 by flow analysis with chemiluminiscent detection
Svobodová, Kateřina ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
This thesis reports determination of vitamin B12 by flow techniques of analysis. This method is based on luminol-peroxide chemiluminiscence assay for the detection of cobalt (II) ions in vitamin B12 molecules. The method includes releasing of Co2+ from the vitamin B12 using different types of its decomposition; these are mentioned in this thesis. The efficiency of the decomposition of real samples of vitamin B12 in this study reached 74.43 %. The high efficiency was achieved with 1.5 mmol.l-1 K2S2O8 and irradiation time 1 minute. In the FIA mode, the linear range obtained was between 1.0 to 500 mg.l-1 with a relative standard deviation (RSD) 2.59% (n = 10), limit of detection (LOD) 55 µg.l-1 . The minimum sample volume required and the time of analysis were 60 µl and 140.2 s. In the SIA mode, the linear range obtained was between 0.01 to 50 mg.l-1 with an RSD = 4.5% (n = 10), LOD = 25 µg.l-1 . The minimum sample volume required and the time of analysis were 250 µl and 80.1 s. Interference study showed that from wide range of interfering ions were selected only Ni2+ , Zn2+ and NO2 - , that from concentration level 50 mg.l-1 they significantly affect the determination of the Co2+ in solution. The intensity of chemiluminiscence most suppress ion Zn2+ . The solution with the concentration ratio of Co2+...

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