Sökning: "Centrum för analys och syntes"

Visar resultat 31 - 35 av 266 avhandlingar innehållade orden Centrum för analys och syntes.

1. 31. A study of the stereochemistry and electronic transitions of cyclic and acyclic thioamides by crystallography, spectroscopy and computational methods

   Författare :Knut Rang; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; UV and CD spectroscopy; rotational barriers; DNMR; X-ray; N -bis[ S -1-phenylethyl]-thiourea; N; attractive steric effect; chiral; phenyl or H- rhodanines; 3- alkyl or aralkyl -5- methyl; Conformations; electronic transitions; molecular mechanics; enantiom; Organic chemistry; Organisk kemi;

   Sammanfattning : Analysis of conformations and electron transitions of 3-(alkyl or aralkyl)-5-(methyl or phenyl)rhodanines with analogues and N,N'-bis[(S)-1-phenylethyl]-thiourea have been performed by X-ray crystallography, 1H NMR, molecular mechanics, ultraviolet spectroscopy and for the chiral rhodanines, enantiomer chromatography and circular dichroism spectroscopy. The magnitude of rotational barriers has been determined. LÄS MER

3. 32. Development and Application of Enzyme- and Antibody-based Assays with Emphasis on Selectivity, Sensitivity and Stability

   Författare :Catalin Nistor; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stability; sensitivity; selectivity; cross-reactivity; sample matrix effects; environmental pollutants; enzyme biosensor; immunoassay; Analytical chemistry; Analytisk kemi;

   Sammanfattning : This thesis presents the development, optimisation, and various applications of enzyme-based biosensors and immunoassays, mainly with relevance to environmental analysis. the thesis discusses problems and possible solutions associated with selectivity, sensitivity and robustness of such bioassays with emphasis on various immunoasssay configurations for determination of surfactants, phenols, or drugs, and amperometric biosensors based on enzymes (e. LÄS MER

4. 33. Studies of Electrocatalytic Reactions of NADH at Mediator Modified Electrodes and of H2O2 at Peroxidase Modified Electrodes

   Författare :Florentina Munteanu; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electrochemistry; Elektrokemi; kinetic studies; silica gel; titanium phoshate; zirconium phosphate; NADH; redox mediator; phenolic compounds; hydrogen peroxide; electron transfer; graphite and carbon paste electrodes; peroxidase; biosensor;

   Sammanfattning : This thesis addresses: (1) studies of direct and mediated electron transfer and kinetics of peroxidases on electrodes and the development of amperometric peroxidase-based biosenors, (2) electrochemical and kinetic studies of NADH oxidation at mediator modified electrodes. The direct and mediated electron transfer of horseradish and tobacco peroxidase were investigated on graphite electrodes by using wall-jet electrode methodology. LÄS MER

5. 34. On-line Sample Pretreatment Based on Membrane Enrichment, Mainly Using Supported Liquid Membranes, for Chromatographic Analysis

   Författare :Yin Shen; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biological Sample; Environmental Sample; Capillary Gas Chromatography; Ion Chromatography; Automation; Sample Pretreatment; Enrichment; Membrane; Extraction; Analytical chemistry; Analytisk kemi;

   Sammanfattning : The main objective of this work was to construct practical analytical systems for the analysis of environmental and biological samples, using membrane-based techniques for sample pretreatment and chromatography for final analysis. Two types of membrane processes have been applied, with emphasis on automation. LÄS MER

7. 35. C-H Activation Reactions Mediated by Pd Based Heterogeneous Catalysts : Regioselective Formation of C-O and C-X Bonds

   Författare :Maitham Majeed; Centrum för analys och syntes; []
   Nyckelord :C-H Activation; N-heterocyclic carbenes; palladium; polymer supported Pd II ; undirected acetoxylation; directed halogenation; continuous flow; reduced graphene oxide supported Pd II ;

   Sammanfattning : New classes of N-heterocyclic carbene-palladium(II) complexes containing either a vinyl group in different positions or an anthracene tag in the backbone of the N-heterocycle were synthesized and fully characterized. The vinyl based complexes were copolymerized with divinylbenzene to fabricate robust polymer-supported NHC-Pd(II) systems, while the anthracene based complexes were π-stacked onto the surface of reduced graphene oxide (rGO) producing immobilized catalysts with interesting features. LÄS MER