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Ablation chamber for a combination of LIBS and LA-ICP-MS techniques
Sovadina, Petr ; Kuchynka, Michaela (referee) ; Novotný, Jan (advisor)
Laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) are spectroscopic techniques that use a pulsed laser to ablate the material in their analysis. Although LA-ICP-MS can reach a much lower detection limit than LIBS, it is not able to detect elements of organic compounds, halogens, and noble gases. By combining these two spectroscopic techniques, it is possible to overcome these shortcomings, to analyze all elements with LIBS, and also to analyze with a lower detection limit with LA-ICP-MS. To perform this combination of spectroscopic techniques, it was necessary to design an ablation chamber that would simultaneously support both LIBS and LA-ICP-MS measurements. The design of the ablation chamber consists of the mechanical design, the simulation of the gas flow inside the chamber, and finally its fabrication and assembly.
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LIBS detection of trace elements in polymeric matrice
Kočenda, Dominik ; Kopřivová, Hana (referee) ; Krčma, František (advisor)
When recycling plastic materials, it is important to determine whether they contain concentrations of hazardous impurities, such as heavy metals, above permissible limits. This bachelor's thesis focuses on quantifying cadmium in a polymer matrix using Laser-Induced Breakdown Spectroscopy (LIBS). Samples of polypropylene and polystyrene with unknown cadmium concentrations were examined. Calibration samples for both types of polymers were prepared for quantification and then analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in an external laboratory. These results were used as calibration values for the LIBS method and also to verify the accuracy of the obtained results. Calibration curves for cadmium were created from the calibration samples, which enabled the determination of unknown cadmium concentrations in the polypropylene and polystyrene samples and the determination of the detection limit of cadmium using the LIBS method. Cadmium in the unknown samples was quantified with an average accuracy of 90 % and precision of 85 %.
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Modification of Targeting Camera for a Remote Laser Spectroscopy
Klempa, Tomáš ; Ficza, Ildikó (referee) ; Brada, Michal (advisor)
The bachelor thesis deals with the modification of targeting camera for remote laser spectroscopy. Targeting camera will be used on remote laser spectroscopy unit to study its features in laboratory of Institute of Physical Engineering on University of Mechanical Engineering Brno and to study the affect of external environment to analytic ability. The thesis contains a brief overview of the current stage of knowledge, designs of stroctural variations and the description of parts of designed device.
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Detection of luminescent nanoparticles in plants by laser spectroscopy
Střítežská, Sára ; Novotný,, Karel (referee) ; Modlitbová, Pavlína (advisor)
This diploma thesis deals with evaluation of toxicity and bioaccumulation of photon-upconversion nanoparticles (UCNPs) in model plant maize (Zea mays). Lanthanide-doped UCNPs with different composition and size were tested in three different concentrations in this work. The exposure took place for 168 hours. Toxicity was assessed based on four macroscopic toxicological endpoints (mortality, the length of belowground part of the plants, the length of aboveground part of the plants and whole plants length). Spatial distribution of elements yttrium, ytterbium, erbium and gadolinium in model plants was determined using laser induced breakdown spectroscopy with spatial resolution of 100 m and 26 m. Distribution of UCNPs in plants was further studied with photon-upconversion microscanning with spatial resolution of 40 m. Stability of UCNPs during and after the plant exposure was also discussed in this thesis.
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Creation of spectral lines database of selected standards for Laser-induced Breakdown Spectroscopy (LIBS) and double pulse Laser-induced Breakdown Spectroscopy (DP LIBS)
Mazura, Martin ; Sládková, Lucia (referee) ; Kaiser, Jozef (advisor)
Laser-Induced Breakdown Spectroscopy (LIBS) has a great potential across a different fields of use. Wide use of this method is still complicated because of some problems. The most important problem is difficult analysis of obtained measurement results. Nowadays mostly used analysis is based on comparison of measured data with databases created in different way. This bachelor’s thesis deals with creation of spectral lines database for LIBS and it also shows the methodology for spectral lines database assembling. Theoretical basis of the method and experimental setup used for measurements is described in the first part of this thesis. Further, there are described measurements of standards and creation of database. The result of this work presents a database of spectral lines containing 14 elements and more than 500 spectral lines. In order to illustrate database utilization it was established composition of an unknown sample.
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Impact of the atmosphere on laser ablation of matters
Černá, Svatava ; Hrdlička, Aleš (referee) ; Pořízka, Pavel (advisor)
This thesis deals with a general overview of laser-induced breakdown spectroscopy - ablation of material and plasma formation when a change of the surrounding environment occurs. The aim is to establish ideal conditions for improving detection, which is difficult for some elements when the measurement takes place in the ambient atmosphere. This is the reason why we change the ambient conditions, the gas (air, helium, argon) and its pressure. Buffer gases (helium, argon) influence the development of the material ablation and quality of generated plasma. That is why we inspect the changes in the signal according to particular atmospheres (signal change in buffer gases compared to the ambient atmosphere). The first part of the thesis presents the principle and physical nature of laser ablation with a brief search of experiments performed so far for similar purposes. Based on this search we determine conclusions about the influence of buffer gasses and pressure on the detection used gasses. In the second part of the work, the controlled experiment is presented, which consisted of the detection of spectral lines of fluorine and potassium, see chapter 5.6 and molecular transitions of calcium fluoride, see chapter 5.10. In a controlled experiment, we established two assumptions. The first assumption is the influence of the inert gas atmosphere, which should significantly improve the detection of fluorine and potassium compared to the air atmosphere. We confirmed this finding only for the argon atmosphere. In contrast, in the helium atmosphere, the detection of none of the elements improved. The second assumption is the effect of reducing the ambient pressure, which in combination with an inert gas should allow the detection of fluorine even at low concentrations in the sample. We consider the measured glass disk in chapter 5.7 to be such a sample. This assumption is not confirmed, as the increased intensity of the fluorine spectral line does not manifest itself in any way when the pressure in the vacuum chamber decreases. Finally, in chapter 7 from the results of individual parts of the experiment, the most suitable conditions for the future detection of the measured substances were proposed: fluorine, potassium and calcium fluoride molecules.
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Analysis of biotic matrices by Laser-Induced Breakdown Spectroscopy
Střítežská, Sára ; Karel,, Novotný (referee) ; Modlitbová, Pavlína (advisor)
This bachelor thesis discusses the possibility of using Laser-induced breakdown spectroscopy (LIBS) for biological application. The LIBS method was used to determine spatial distribution of a chosen element, cadmium, in selected model plant, white mustard (Sinapis Alba L.) The exposure took place in hydroponic conditions and lasted for 72 hours, therefore it was an acute toxicity test. Three different sources of cadmium were tested, mercaptopropionic acid stabilized quantum dots (CdTe QDs), silica coated quantum dots (CdTe/SiO2 QDs), and cadmium chloride, which was used as a positive control. After the exposure and before determination of the spatial distribution of cadmium in plants, a significant portion of the thesis was devoted to optimization of selected parameters of LIBS measurement (laser energy and gate delay). Subsequently, the cadmium distribution was determined and the obtained results were discussed with regards to the tested substance, its stability and its tendency to aggregate/agglomerate in water medium in contact with testing organism during exposure. In the final part of the work, the suitability of the LIBS method for the determination of spatial distribution of chosen contaminants was evaluated.
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Detection of heavy metals in hard tissues by laser-induced breakdown spectroscopy
Konečná, Anna ; Novotný, Karel (referee) ; Pořízka, Pavel (advisor)
This master thesis deals with the detection of heavy metals bioaccumulated in hard tissues by laser-induced breakdown spectroscopy (LIBS). As model samples, murine mandibles and femurs of animals exposed to lead oxide or cadmium oxide nanoparticles were used. The exposure of animals lasted for 6 or 7 weeks. Control group of animals was exposed only to air for a reference. The distribution of biogenic elements and contaminants was determined by mapping the samples' surface using LIBS with a spatial resolution of 30 and 100 µm. The second part of the work focused on the possibility of using the method LIBS for quantitative analysis. Samples of hydroxyapatite standards were prepared as reference material. By their analysis a calibration curve was constructed, and the limits of detection and quantification were determined. Furthermore, a model for prediction of heavy metal concentration by calculation from the calibration curve was presented.
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Possibilities of using laser spectroscopy for the analyses of inorganic binders and concrete
Kratochvilová, Lucie ; Hrdlička,, Aleš (referee) ; Opravil, Tomáš (advisor)
This master’s thesis is dealing with the possibility of using laser-induced breakdown spectroscopy for the detection of non-metallic elements (e. g. chlorine) in concrete. These elements cause degradation of concrete which leads to a shortening lifetime of reinforced concrete buildings. In the experimental part of thesis, a methodology for the determination of chlorides in concrete will be created and verified. A comparison of the single pulse and the double pulse configuration of the LIBS will be done on the samples containing only pure chemical substances with known concentrations of chlorine.
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