Sökning: "analytisk kemi"

Visar resultat 36 - 40 av 601 avhandlingar innehållade orden analytisk kemi.

1. 36. Novel clean-up, concentration and laser desorption/ionization strategies for mass spectrometry

   Författare :Mohammadreza Shariatgorji; Leopold Ilag; Juan Astorga-wells; Bernhard Spengler; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mass spectrometry; ESI-MS; SALDI-MS; Electrocapture; Sample treatment; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : Despite valuable advantages of mass spectrometry (MS) techniques they still have drawbacks that need to be overcome, notably their sensitivity to various kinds of interfering substances and associated difficulties involved in detecting signals from analytes present in trace quantities. Thus, high quality analytical data could be acquired by improving sample pre-treatment techniques and/or ionization methods to increase ionization yields and/or avoid the generation of unwanted ions. LÄS MER

3. 37. Mass Spectrometry of Biologically Active Small Molecules : Focusing on polyphenols, alkaloids and amino acids

   Författare :Zdeněk Spáčil; Leopold L. Ilag; Frantisek Turecek; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LC-MS; LDI; Mass spectrometry; HPLC; UHPLC; polyphenols; phenolic acids; BMAA; Separation methods; Separationsmetoder; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : The foci of this dissertation are on advanced liquid chromatography (LC) separation and mass spectrometry (MS) techniques for the analysis of small bioactive molecules. In addition to discussing general aspects of such techniques the results from analyses of polyphenols (PPs), alkaloids and amino acids published in five appended studies are presented and discussed. LÄS MER

4. 38. Colloidal/Solid Phase Extraction (C/S PE) Methods Based on Hydrogel Nanoparticles, Titanium dioxide microparticles and Empore Membranes Applied to Biological and Environmental Matrices

   Författare :Davide Tamburro; Leopold Ilag; Robin Couch; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; biomarkers; nanogels; solid-phase extraction; organophosphate esters; peptides; mass spectrometry; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : The aim of the work described in this thesis was to create and develop novel technologies in order to overcome barriers and hurdles that analytical chemistry faces focusing on sample extraction. In paper I dye containing amine groups (e.g. LÄS MER

5. 39. Retention time predictions in Gas Chromatography

   Författare :Yasar Thewalim; Anders Colmsjö; Torgny Fornstedt; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gas chromatography; computer simulation; two-parameter model; retention time prediction; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : In gas chromatography, analytes are separated by differences in their partition between a mobile phase and a stationary phase. Temperature-program, column dimensions, stationary and mobile phases, and flow rate are all parameters that can affect the quality of the separation in gas chromatography. LÄS MER

7. 40. New methods for determination of airborne pollutants : Focus on tetrabromobisphenol A, organophosphate triesters and polycyclic aromatic hydrocarbons

   Författare :Johanna Tollbäck; Ulrika Nilsson; Peter Haglund; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Air sampling; sampling methods; indoor air; SPE; SPME; extraction; dynamic extraction; online coupling; SWE; subcritical water extraction; GC MS; LC MS; organophosphate triesters; PAH; tetrabromobisphenol A; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : The work presented in this thesis concerns the development and evaluation of new methods of sampling and analysis of organic pollutants in the indoor and outdoor environment. In Paper I, the development of a new method was reported for the determination of the brominated flame retardant tetrabromobisphenol A (TBBPA) in air using sampling with glass fiber filter and polyurethane foam (PUF), ultrasonic solvent extraction and liquid chromatography coupled to electrospray ionisation mass spectrometry (LC-ESI/MS). LÄS MER