Browsing by Subject "fragmentoituminen"
Now showing items 1-2 of 2
-
(2014)The literature review deals with the structure of arabinoxylan and the principles of mass spectrometric methods used in analyzing them. The fragmentation of carbohydrate structures, the structural information gained from it, and naming of the resulting neutral fragments and product ions was also discussed. The aim of the experimental work was to analyze linear xylo-oligosaccharides and branched or linear arabinoxylans with known structures using tandem mass spectrometry. Of the arabinoxylo-oligosaccharides analyzed, three were branched while the others had an arabinose substituent at terminal xylose. The oligosaccharides were analyzed as underivatized, alditols, and methylated alditols with both positive and negative ionization. Derivatization was done in order to produce different product ions and to gain information about the effect of reduction and methylation on fragmentation mechanisms. Underivatized oligosaccharides provided most information with negative mode ionization. Low intensity of C-type fragment ions prevented their isolation in MS3-step when reduced oligosaccharides were analyzed. Methylation changed the weights of fragmentation products, which made it possible to detect branching in the oligosaccharide structure. Methylation also changed the fragmentation mechanism which caused differences in the product ion spectra compared to underivatized oligosaccharides. B-ions were fragmented to gain information about linkage positions when analyzing methylated alditols. The mechanism of B-ion fragmentation differs from that of C-ions, and produced information rich neutral fragments. However, low signal intensity made branch site analysis difficult, especially when arabinose substituent was located at terminal xylose.
-
(2016)In tablet compression the objective is to obtain a durable tablet. The main deformation mechanism of substance affects how good tablet is obtained. The pharmaceutical powders is often divided into two categories with respect to their principal deformation mechanism: plastic and fragmented. Good tablet formulation requires its components to deform with both of these mechanisms. It is possible to examine in many ways, whether material is plastic or fragmented. These include force-time graphs and indentation methods, as well as different compression equations such Heckel equation. Examination and identification of the deformation mechanisms is important in order to design a formulation which provides the most durable tablet. The aim of experimental work in this study was to test the new compression device and method, and to compare the results of the device shown in the earlier literature results. Comparison with previous research, new in this study was compression rate and without a motor acting compaction system. In this study, there was two compression method developed, dynamic and static. Data from a dynamic method were analysed by time-travel - and force-displacement -curves. Results were parameterized, and on the basis of these parameters the behaviour of various materials was evaluated and compared to the earlier literature. Relaxation study was also performed in this research. The results of these measurements were analysed with the parameterized function fit, after which the results were compared with earlier results presented in the literature. The results of this work in dynamic measurements are cosistent with the research results received earlier. In terms of almost all parameters investigated, substances were divided into two groups in the same way as in the previous literature on the basis of the main deformation mechanism. The results obtained in static measurements, however, were quite inconsistent with previous research. Based on the results it can be stated that the method makes it possible to get consistent results with the literature. However, the method still requires development, and possible error sources and the choice of analytical method should pay special attention.
Now showing items 1-2 of 2