Sökning: "isotopic exchange"
Visar resultat 11 - 15 av 18 avhandlingar innehållade orden isotopic exchange.
11. Isotope analysis of trace and ultra-trace elements in environmental matrices
Sammanfattning : High precision isotope ratio measurements have found increasing application in various branches of science, from classical isotope geochronology to complex multi-tracer experiments in environmental studies. Progress in analytical technologies in recent years has allowed higher quality data to be obtained through mass spectrometry. LÄS MER
12. Method development for isotope analysis of trace and ultra-trace elements in environmental matrices
Sammanfattning : The increasing load of toxic elements entering the ecosystems, as a consequence of anthropogenic processes, has grown public awareness in the last decades, resulting in a great number of studies focusing on pollution sources, transport, distribution, interactions with living organisms and remediation. Physical/chemical processes that drive the uptake, assimilation, compartmentation and translocation of heavy metals in biota has received a great deal of attention recently, since elemental concentrations and isotopic composition in biological matrices can be used as probes of both natural and anthropogenic sources. LÄS MER
13. Long-term phosphorus supply in agricultural soils : size and dynamics of fast- and slow-desorbing phosphorus pools
Sammanfattning : To improve phosphorus (P) fertiliser management, a better understanding of inorganic P exchange between the soil solution and solid phase is needed. This thesis examined the dynamics of this exchange, distinguishing between pools of P that are fast- and slowdesorbing, and compared methods for quantification of these pools. LÄS MER
14. Late-stage 11C-carbonylation of drug-like molecules for PET
Sammanfattning : Positron emission tomography (PET) is a non-invasive in vivo imaging technique used for translational biomedical research and clinical diagnosis. A fundamental pre-condition for PET is the radiolabelled tracer molecule used in the emission measurement, and there is a pressing need to accelerate the development of novel PET tracers to meet an increasing demand from the healthcare system, academia and drug industry. LÄS MER
15. Fractionation of Fe and Zn isotopes : methods and some applications in aqueous geochemistry
Sammanfattning : Multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS) has been used for the measurement of Fe and Zn isotope ratios in a variety of sample types including natural and synthetic waters, ferromanganese concretions, sediments and biological material. The focus of this PhD study was the development of analytical procedures for precise and accurate measurement of Fe and Zn isotope ratios by high resolution MC-ICPMS. LÄS MER
