Microfluidics miniaturizes many benchtop processes and provides advantages of low cost, reduced reagent usage, process integration, and faster analyses. Microfluidic devices have been fabricated from a wide variety of materials and methods for many applications. This dissertation describes four such examples, each employing different features and fabrication methods or materials in order to achieve their respective goals. In the first example of microfluidic applications in this dissertation, thermoplastics are hot embossed to form t-shaped channels for microchip electrophoresis. These devices are used to separate six preterm birth (PTB) biomarkers and establish a limit of detection for each. The next chapter describes 3D printed devices with reversed-phase monoliths for solid-phase extraction and on-chip fluorescent labeling of PTB biomarkers. I demonstrate the optimization of the monolith and selective retention of nine PTB biomarkers, the first microchip study to perform an analysis on this entire panel. The third project describes the iterative design and fabrication of glass/polydimethylsiloxane (PDMS) devices with gold and nickel electrodes for the self-assembly of DNA nanotubes for site-selective placement of nanowires. Simple flow channels and “patch electrode” devices were successfully used, and DNA seeding was achieved on gold electrodes. Finally, a 3D printed device for cancer drug screening was developed as a replacement for one previously fabricated in PDMS. Devices of increasing complexity were fabricated, and those tested found to give good control over fluid flow for multiple inlets and valves. Although the applications and methods of these projects are varied, the work in this dissertation demonstrates the potential of microfluidics in several fields, particularly for diagnostics, therapeutics, and nanoelectronics. Furthermore, it demonstrates the importance of applying appropriate tools to each problem to gain specific advantages. Each of the described devices has the potential for increased complexity and integration, which further emphasizes the advantages of miniaturized analyses and the potential for microfluidics for analytical testing in years to come.

Oil spills, especially in water have happened throughout the years. The consequences from this kind of incident have always been a threat to marine life and take a lot of money and time to clean up. The forensic investigations of oil usually focus on oil spill in water, however, this kind of investigation can be applied on more areas, such as in sexual offense cases and arson. The oil from the crime scene and the oil from the suspected source are analyzed and compared to each other to see if the compositions match. The aim of this thesis was to optimize the clean-up process of heavy fuel oil (HFO) using solid-phase extraction (SPE) according to the European Committee for standardization (CEN) 15522-2 method. HFOs are black oils, containing particles and soot which will decrease injector performance. Thus, a cleanup procedure is attractive when analyzing such samples. The three factors of optimization in this study were elution volumes, solvents, and SPE sorbents.The SPE method used in this study was to use the cartridges as a filter; therefore, the samples were both loaded and eluted with an organic solvent, in this case dichloromethane (DCM) or dichloromethane/heptane (DCM/Hp). The gas chromatography mass spectrometry (GC-MS) analysis method used is described in Annex B in the CEN 15522-2 method.Concluding, increasing the eluent volume did not indicate improvement on the extraction method. In terms of the solvents, both dichloromethane and dichloromethane/heptane showed similar results. The percentage weathering plots (PW-plots) showed that the SPE sorbents (dual layer florisil/Na2SO4, florisil and silica gel sorbents) worked similar. The overall conclusion from this thesis work was that further optimization must be made before implementing the method.

Over the last several decades, there have been a tremendous developments and greatinnovations in photocatalysis process along with the development of efficient nanosized catalysts for simple approach and economic viability. In this study, magnetic core@doubleshell nanomaterials were investigated and synthesized in lab with three-step innovative approach where Fe3O4 nanoparticles (NPs) were produced first to act as cores without using any surfactants. The magnetite/silica core–shell structure was then prepared by hydrolysis of tetraethoxysilane (TEOS) in the presence of core particles under alkaline conditions. And the outermost shell, the α-Fe2O3/TiO2 nanoparticles, were grown over magnetic core of Fe3O4@SiO2 using coprecipitation and calcination method. Furthermore, the Fe3O4@SiO2@α-Fe2O3/TiO2 NPs were then loaded on the reduced graphene oxide (r-GO) using hydrothermal method and are also mixed by kneading with the layered double hydroxides (LDH) of Mg2+ and Al3+. These nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDS). Different model compounds like microcrystalline cellulose (90 μm), D-xylose, and sodium lignosulfonate representing cellulose, hemicellulose, and lignin, respectively, were converted to valuable chemicals with different NPs under visible light for different time periods. For example, valeric acid (VA) and vanillylmandelic acid (VMA) were produced when cellulose was used for the conversion with core-double shell NPS which were quantified using high performance liquid chromatography (HPLC). Similar approach was adopted for the conversion of brewers’ spent grain (BSG), a lignocellulosic biomass, without oxygen under visible light, which yielded ethanol as the main product along with other sugars and acids of very low concentrations. The magnetic property of the nanomaterials made it easy for recycle and reuse. From a sustainability point of view, this study will fill a large need in the biomass photocatalysis field by developing core-shell multi-functional photocatalysts for direct transformation of lignocellulose into valuable chemicals under low temperatures, atmospheric pressure, and visible light from the sun.

The focus of the work is on the epitaxial growth of Mn5Ge3 layers on Ge (001) via ultra-fast solid-state reaction between Mn and Ge using millisecond range FLA at the ambient pressure in continuous N2 flow. Epitaxial Mn5Ge3 layers were obtained both on Ge (001) and Ge (111) substrates by optimizing the fabrication parameters, Mn thickness (30 nm), FLA energy density (100-110 Jcm-2) and FLA duration time. The epitaxial relationship between the alloy film and substrate is the (100) plane of Mn5Ge3 along [001] direction parallel with the [100] direction of Ge (001) plane. It is notable that the hexagonal c axis of Mn5Ge3 on Ge (001) is parallel to the film surface plane, while the reported Mn5Ge3’s c axis on Ge (111) tends to be perpendicular to the film plane. In fact, using ultrafast-SPE the c-axis of Mn5Ge3 is always parallel to the sample surface. Mn5Ge3 films exhibit ferromagnetism which is demonstrated by the anomalous Hall effect up to the TC = 283±5 K. The films exhibit their in-plane magnetic easy axis along the hexagonal c-axis independent of the Mn5Ge3 film thickness. This provides a new avenue for the fabrication of Ge-based spin-injectors fully compatible with industrial CMOS technology. The deeper understanding of the magnetic, structural and electrical properties of (100) epitaxial Mn5Ge3 grown on Ge (001) are presented by utilizing DFT calculation (by our collaborator M. Birowska) and various experimental methods. The Mn atoms in Mn5Ge3 occupy two distinct Wyckoff positions with fourfold (Mn1) and sixfold (Mn2) multiplicity. During cooling down to 100 K the Mn5Ge3 unit-cell shows remarkable structural deformation. The nearest distance d3 between Mn2-Mn2 atoms in the hexagonal a-b plane is shortened much faster than the nearest distance d1 between Mn1-Mn1 atoms along hexagonal c axis. The DFT calculations show that below critical distance d3 < 3.002 Å, the Mn2 atoms are AFM coupled while for d3 > 3.002 Å the coupling is FM. The FM coupling between Mn1 atoms weakly depends on the atomic distance d1. Moreover, there is a transition from collinear to noncollinear spin configuration at about 70±5 K. Simultaneously, at low temperature, the angular dependent magnetoresistance shows a switching from multi-fold component to twofold symmetry. The combination of different experimental techniques with theoretical calculations enabled us to conclude that the switching between non-collinear and collinear spin configurations and the variation of anisotropic magnetoresistance in Mn5Ge3 is due to the strain induced change of the magnetic coupling between Mn2-Mn2 atoms. Finally, the effects of strain on the structural and magnetic properties of epitaxial Mn5Ge3 on Ge (111) substrate by applying ms-range FLA are investigated. The X-ray diffraction results demonstrate that during FLA process the formation of nonmagnetic secondary phases of MnxGey is fully suppressed and the in-plane tensile strain is enhanced. The temperature dependent magnetization indicates that after FLA the Curie temperature of Mn5Ge3 increases from 283±5 K to above 400 K. Further Monte Carlo simulations manifest that the change of the strain in Mn5Ge3 during ms-range FLA modifies the distance between adjacent Mn atoms in the hexagonal basal plane, which provokes the different ferromagnetic interaction between them. Consequently, the significant increase of Curie temperature is observed. This provides a good way to improve the Curie temperature of Mn5Ge3 which is promising to realize room-temperature operated Ge based spin-injectors.

The diploma thesis focuses on identifying the presence of platinum in soil samples by absorption spectroscopy. The work is divided into two parts, the theoretical part is focused on the occurrence and behavior of platinum in the environment, the fundamental chemical and physical properties of platinum, its importance in catalytic converters in cars, on solid phase extraction method and the method for the determination of atomic absorption spectrometry. The second part is the practical part, focused on the determination of the platinum amount in the soil samples in the city of Brno.

is is a study of the relationship between structure, mechanical properties and relaxing behavior of the polypropylene. The structure was evaluated by the quantity the solid phase content (SPC). This was defined as mathematical result of free induction decay (FID) signal from pulsed 1H-NMR. The solid phase content is a quite new structural parameter representing the quantity for description of semi-crystalline polymers. Whereas pulsed 1H-NMR is non-destructive, accurate and repeatable, it becomes a unique tool for a description of mechanical, structural, physical-mechanical changes of polypropylene within the time and temperature. Particularly, this method registers the small changes in the time-dependant shipments during secondary crystallization with small structure changes.

Polychlorinated biphenyls (PCBs) are a class of important organic pollutants which undergo very slow degradation and tend to persist for a long time in the environment. PCBs have various negative effects on living organisms, human health and the environment in general. A method for determining PCB levels in aqueous matrices was developed consisting of solid-phase extraction (SPE) and GC/MS determination. The average recoveries of PCB congeners from artificially spiked deionized water were around 85%. The PCB concentration of 3.3±0.1 μg·l-1 (a sum of selected congeners) was detected in contaminated groundwater originated from the area of a former asphalt concrete producing plant. The most abundant PCBs were trichlorinated congeners which together comprised about 80% of the total PCB content. The optimised SPE method was further applied together with accelerated solvent extraction (ASE) to assess the degradation potential of oyster mushroom (Pleurotus ostreatus) which shows high degradation efficiency of various organic pollutants including PCBs. P. ostreatus belongs to ligninolytic (white-rot) fungi, which is a very promising group of microorganisms frequently studied due to their bioremediation potential. P. ostreatus, strain KRYOS was able to remove 41±8% of the initial amount (50 μg) of the...

Seit 2002 kam ein neues Interesse an Germanium als Material für CMOS-Bauelemente auf, angetrieben durch die höhere Beweglichkeit der Ladungsträger im Vergleich zu Silizium. Für die Herstellung von Germanium MOSFETs bestehen allerdings noch einige Herausforderungen. Speziell die Problematik der hohen n-Dotierung für die Source- und Draingebiete der PMOS-Transistoren hat sich dabei als potentieller Roadblocker herauskristallisiert. Die geringe Aktivierung und die hohe Diffusivität der Donatoren in Germanium stellen ein Problem für die Herstellung von CMOS-Schaltkreisen aus Germanium dar. Als ursächlich dafür wurden Vakanzen identifiziert (Bracht et.al.). Um das Diffusions- und das Aktivierungsverhalten von Arsen und Phosphor in Germanium zu untersuchen, wurden p-Typ Germaniumwafer durch Ionenimplantation mit beiden Spezies dotiert und anschließend durch Rapid-Thermal-Annealing und/ oder Flash-Lamp-Annealing ausgeheilt. Zusätzlich wurden Experimente mit kodotierten und P-dotierten Proben mit verringerter Schichtkonzentration durchgeführt. Untersuchungen mit Rutherford-Backscattering-Spektroskopie und Transmissions-Elektronen-Mikroskopie werden durchgeführt, um die strukturellen Eigenschaften der Proben infolge der Implantation und der Ausheilung festzustellen. Mittels Sekundärionen-Massen-Spektroskopie wird die Dotandenkonzentration bestimmt. Es folgen elektrische Messungen des Schichtwiderstandes bei Raumtemperatur und in geeigneten Fällen bei Temperaturen unterhalb 10K. An ausgewählten Proben werden Hallmessungen durchgeführt. Die Gesamtheit der Analyseverfahren ermöglicht eine Analyse des Rückwachsverhaltens, der Diffusion und der elektrischen Aktivierung der Dotanden unter den verschiedenen Implantations- und Ausheilbedingungen. Die nach verschiedenen Methoden bestimmten Größen wie die Ladungsträgerkonzentration und -mobilität werden betrachtet und im Hinblick auf die Parameter der Probenpräparation analysiert und mit der Literatur verglichen. Abschließend werden mögliche Mechanismen zur Deaktivierung von Donatoren in Germanium erörtert.

The diploma thesis deals with the development of a new method of synthetic peptide separation using electrostatic binding. It deals with the development of a multi-charged anchored linker attachable to a synthetic peptide after its synthesis on solid phase. Subsequently, it investigates the separation using electrostatic binding; however, after peptide cleavage from the anchored linker and Boc deprotection with TFA, the peptide formed so strong electrostatic interactions with the cation exchanger that we were unable to recover it. The thesis is finished with discussion and method improvement proposal. Key words: peptide separation, solid-phase peptide synthesis, SPPS, electrostatic binding

In forensic toxicology, opioids are frequently associated with drug abuse or drug-related death cases. An optimal method for use in the identification and quantification of opioids in a complex blood matrix is of paramount importance. Along with the ability to identify and quantitate opioids, this method should be accurate, sensitive, and selective. The application of sample pre-treatment and solid-phase extraction are common to purify and concentrate the target analytes before analyzing with liquid chromatography-tandem mass spectrometry. The purpose of this study was to compare the performance of two standard operating procedures, adopted by the Massachusetts State Police Crime Laboratory Toxicology and the Biomedical Forensic Sciences– Toxicology Laboratory at Boston University School of Medicine, for detecting opioids in blood. A total of eight drugs were analyzed: 6-monoacetylmorphine, codeine, fentanyl, hydrocodone, morphine, norhydrocodone, oxycodone, and oxymorphone. Comparison was performed using the parameters studied as part of method validation, including calibration model, bias, precision, carryover, interferences, ionization suppression/enhancement, and recovery. The results indicated that the method from Massachusetts State Police provided a better performance with between-run precision, interferences from matrix and other commonly encountered drugs, matrix effect at high concentration (250 ng/mL) and matrix recovery. Meanwhile, the method from Biomedical Forensic Sciences showed less bias, within-run precision, and matrix effect at low concentrations. Carryover and internal standard interference were comparable in both standard operating procedures. The calibration models were adjusted by altering the selection of regression model for improved quantification method performance. The volume of solvents, sample matrix, as well as time, were taken into consideration in accessing the overall performance of identification and quantitation. Both procedures were comparable yet the one from Massachusetts State Police was more beneficial in identifying the target analytes with greater sensitivity and selectivity and the one from Biomedical Forensic Sciences was more economical and efficient.