National Repository of Grey Literature 28 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Elemental analysis of leaf and soil samples using the ICP-MS
Švecová, Pavla ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
EN Theaimofthisthesiswastodeterminethecontentofselectedelements,namelyarsenic,cadmium, copper, nickel, lead, calcium, and zinc in leaf and soil samples. The analysed samples were received from many locations in the Czech Republic and various European countries. Leaf samples were dried and digested in a microwave digestion system for the determination of thetotal content ofelements.Soil samples wereanalysed usinganextractionprocedurewithaquaregiaas the extractant according to ISO 11466. This method was also applied to certified reference materials to verify the usage of this procedure. The content of elements in leaf and soil samples was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Thecontentofelementsinleavesshowedawiderangeofvaluesforeachelement.Concentrations of elements ranged for calcium 0.98 to 16.6mg g-1 , nickel 0.16 to 10.20μg g-1 , copper 2.60 to 43.80 μg g- 1 , zinc 13.4 to 489 μg g-1 , arsenic 0.01 to 11.60 μg g-1 , cadmium < LOD to 7.02 μg g-1 , and lead 0.03 to 71.40μg g-1 , respectively. Generally, higher values of heavy metals were obtained for samples from areas with mining activities or from industrial zones. Recoveryofelementsintheusedcertifiedreferencematerialsshowedvaluesrangingfrom68.4% to 121%. Two types of reference materials were used, and the recovery...
Determination of toxic and essential elements in plants
Filipčíková, Marcela ; Vespalcová, Milena (referee) ; Vitoulová, Eva (advisor)
The aim of diploma thesis is occurrence of toxic and essential elements in vegetables and fruit, especially in fruity baby food. The diploma thesis also dedicates processing of vegetables and fruit for production of baby food. Attention is direct to monitoring of baby food quality in the analytical aspects and also to legislative that is in this area. Samples for analysis are prepared using microwave mineralization and ICP-MS for detection. This is described in the experimental part of the diploma thesis.
Aplication of ICP-MS in environmental analysis and possibilities of this technique for the determination of silicon in waters
Bohdálková, Veronika ; Doležalová Weissmannová, Helena (referee) ; Čáslavský, Josef (advisor)
This bachelor thesis is focused on the application of inductively coupled plasma mass spectrometry (ICP-MS) in environmental analysis. This method offers multi-element analysis on trace and ultra-trace levels as well as isotopic analysis of various species in diverse matrices like drinking, surface and waste waters, sediments, biological samples, food and others. ICP-MS due its high sensitivity, ability of parallel determination of many elements and speed of analysis is more and more applied in the field of pollution control and environmental protection. The main goal of this bachelor thesis is the evaluation of the possibility of silicon determination in various kinds of water by ICP-MS.
Determination of selected metals in grapes cultivated by different techniques
Kubicová, Lenka ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
The aim of this study is to determine the content of selected metals (As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Se, Sn, Sr, Pb, V, Zn) in samples of leaves and grapes produced by ecologic agriculture and compare to results with leaves and grapes produced by integrated agriculture. The measured results used to assess the impact of agricultural technology on the quality of vines and grapes. The amount of elements was analysed using inductively coupled plasma mass spectrometry after previous digestion of sapmles using microwaves. Concentrations of elements in leaves and grapes from organic and integrated farming did not differ significantly only in the case of copper concentrations were measured higher concentrations in samples from organic farming. This difference is probably caused by different doses of authorized protective equipment based on copper in the organic and integrated farming.
Selected inorganic pollutants in foodstuffs
Kroupová, Kateřina ; Vítová, Eva (referee) ; Vitoulová, Eva (advisor)
This bachelor thesis is focus on occurrence of inorganic pollutants in foodstuffs. The introduction is dedicated to apperance of individual selected elements in foodstuffs. Concentration of these elements is very important factor for examination of toxic effects for the human organism. If we want to avoid the harmful effects to the human organism, we have to define border limits. Work is based on the legislative of Czech republic. Second part of this study is focused on the biological monitoring. The biological monitoring is important for precautionary measures. In the third part of this study are described toxical effects of these elements to the human organism. Before qualitative and quantitative analysis by instrumental techniques is important to properly take the sample. In the fourth and fifth part of this work are mentioned methods used for determination of these elements and metods of taking samples. This bachelor thesis provide complex view on the problems of pollutants in foodstuffs and it should be used as a base for following diploma thesis.
Content of toxic and esential elements in bio foodstuffs and their comparing with ordinary foodstuffs
Kohoutková, Nina ; Diviš, Pavel (referee) ; Vitoulová, Eva (advisor)
The aim of this study is to determine the content of toxic and essentials elements in samples of nuts and seeds produced by ecologic agriculture and to compare results with nuts and seeds from conventional agriculture production. These nuts and seeds can be bought in the Czech market (except bio pine nuts, bio pecan nuts and bio pistachios). The amount of elements was analysed using inductively coupled plasma mass spectrometry after previous digestion of samples using microwaves. This study summarizes the main physiological functions of toxic and essentials elements. Results were also compared with another studies. It does not results from all measured amounts of all essential elements, that bio nuts and seeds have higher amounts of these elements; however, all amounts of toxic elements in bio nuts and seeds are lower than in the no-bio ones. For more precise results it would be necessary to measure more samples.
Determination of selected elements in cereal flours and their gluten-free alternatives
Venclová, Veronika ; Hraníček, Jakub (advisor) ; Nováková, Eliška (referee)
This study deals with the determination of calcium, magnesium, phosphorus, potassium, sodium, iron, zinc, copper, manganese and molybdenum in cereal gluten flours and its gluten-free alternatives. The flour samples were digested using a microwave device and the elements in solution were subsequently determined using an inductively coupled plasma mass spectrometer. Optimization of the digestion of the selected flours was performer prior to the actual determination of the elements. The aim of the work was to determine the above listed elements in the flour samples and to establish a basic overview of the elemental composition of the different flours. This overview and comparison of the different flours is intended to help the people with celiac disease to choose gluten-free alternatives to wheat flour. Keywords Inductively coupled plasma mass spectrometry, microwave digestion, calcium, magnesium, phosphorus, potassium, sodium, iron, zinc, copper, manganese, molybdenum, wheat flour, gluten-free flours, celiac disease
Reduction of polyatomic interferences in As and Se determination by ICP-MS
Vajnahij, Volodymyr ; Nováková, Eliška (advisor) ; Hraníček, Jakub (referee)
This bachelor thesis was focused on the eliminationof polyatomic interferences in the determination of As and Se using inductively coupled plasma mass spectrometry. For this purpose, the collision-reaction cell technique was employed. The collision-reaction cell was filled with either collision gas or collision-reaction gas, namely pure He and H2, at different flow rates.In the case of the determinationof arsenic,which is monoisotopic and therefore no isotope other than 75 As can be selected, one of the main polyatomic interferences is 40 Ar35 Cl+ , which has the same mass-to-charge ratio m/z = 75 as 75 As. In the case of selenium determination, there are isobaric interferences due to 40 Ar38 Ar+ , 40 Ar40 Ar+ and 38 Ar40 Ca+ affecting the measurement of 78 Se and 80 Se. When 78 Se was determined in the He mode with 5 ml ∙ min-1 , a 300-fold decrease in BEC was observed. At the same time, this collision gas flow rate is higher than the routinely used one and thus able to remove more polyatomic interferences caused by 40 Ar38 Ar+ and 38 Ar40 Ca+ , respectively.Aslight improvement in some parameters was also achieved by using the H2 mode, which is more effective in reducing polyatomic interferences in the determination of Se than the He mode. With the removal of argide interference, H2 reaction...
Elemental analysis of dendrochronological Norway spruce sample
Zámečník, Karel ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
The subject of this bachelor's thesis is the determination of lithium, sodium, magnesium, potassium, calcium, manganese, iron, zinc, selenium, rubidium, strontium, cadmium, antimony, cesium, barium, and thallium in dendrochronological samples of Norway spruce using inductively coupled plasma mass spectrometry. The samples of the Norway spruce were collected in the autumn of 2018 on the southern slope of hill Melechov in the Vysočina region. The stem sample was first divided into pieces according to the distance from the bark and labelled A1a to A1g. The ash sample was obtained by burning a cross-section of the stem and separating the bark, from which the A3b sample was created. The remaining two samples were made up of needles and twigs and labelled as samples E and F. For elemental analysis, the samples needed to be converted into a solution, which was achieved by dissolving them in a mixture of hydrochloric, nitric, and hydrofluoric acid, using a microwave digestion device. After dissolution, a solution of boric acid was added to each sample solution to complex any unreacted hydrofluoric acid, which could damage the internal components of the ICP-MS. Calibration solutions were then created with concentrations of 0,0016; 0,008; 0,04; 0,2 and 1,0 mg/l from stock solutions containing the analysed...
UV-photochemical generation of volatile species of tellurium and other transition metals
Jeníková, Eva
This dissertation thesis is focused on UV-photochemical generation of volatile species of tellurium, ruthenium, rhenium and iridium coupled to methods of atomic spectrometry. In the first part, attention was paid to the optimization of parameters of UV-photochemical generation of volatile tellurium species and its application for speciation analysis of Te(IV) and Te(VI) in water samples. UV-photochemical generation was carried out in a UV-photoreactor, which consisted of a low-pressure mercury lamp wrapped with a polytetrafluoroethylene reaction coil that served as a reactor. Atomic absorption spectrometry with a continuum source of radiation and high resolution and atomization in a miniature diffusion flame were used to optimize the conditions of generation, which included the composition of the reaction medium, irradiation time and the addition of transition metals as modifiers. In order to achieve a higher sensitivity of determination, the generator was coupled to a triple quadrupole inductively coupled plasma mass spectrometer. Since efficient UV-photochemical generation of volatile species was achieved only from Te(IV), with no response from Te(VI), the feasibility of this technique for simple "non-chromatographic" speciation analysis was tested and a method for determination of Te(IV) and...

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