Sökning: "chromatography matrices"

Visar resultat 21 - 25 av 56 avhandlingar innehållade orden chromatography matrices.

1. 21. Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices

   Författare :Nahid Amini; Gunnar Thorsén; Tuulia Hyötyläinen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sample preparation; SPE; RAM; GCB µ-trap; GCB disk; High temperature LC; LC MS; ESI; APCI; Matrix effects; LIT-MS; SALDI; Sample screening; Oxidized GCB; Silicon nitride; Analytical chemistry; Analytisk kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. LÄS MER

3. 22. Method development for isotope analysis of trace and ultra-trace elements in environmental matrices

   Författare :Nicola Pallavicini; Ilia Rodushkin; Johan Ingri; Frank Vanhaecke; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

   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

4. 23. Mass spectrometry based analysis of endogenous sterols and hormones

   Författare :Neil de Kock; Jonas Bergquist; Kumari Ubhayasekera; William J. Griffiths; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mass spectrometry; supercritical fluid chromatography; UPSFC–MS MS; bioanalysis; steroids; oxysterols; thyroid hormones; Kemi med inriktning mot analytisk kemi; Chemistry with specialization in Analytical Chemistry;

   Sammanfattning : Bioanalytical applications using supercritical fluid chromatography (SFC) as analytical technique are of increasing interest. In essence, bioanalysis involves measurement of bioactive or endogenous compounds in biological matrices. LÄS MER

5. 24. Gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry methods for the determination of environmental contaminants

   Författare :Dawei Geng; Bert van Bavel; Ingrid Ericson Jogsten; Jessika Hagberg; Thanh Wang; Heidi Fiedler; Kees Olie; Örebro universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; PCDD Fs; PCBs; OCPs; PBDEs; NBFRs; APCI; MS MS; HRMS; human serum; osprey egg; Chemistry; Kemi;

   Sammanfattning : The recent developments and improvements of instrumental methods for the analyses of the environmental contaminants, especially the persistent organic pollutants (POPs), have made it possible to detect and quantify these at very low concentrations in environmental and biotic matrices.The main objective of this thesis is to demonstrate the capability of the atmospheric pressure chemical ionization technique (APCI), using gas chromatography coupled to tandem mass spectrometry for the determination of a wide range of environmental contaminants, including the POPs regulated by Stockholm Convention, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), but also the derivates of PBDEs and novel brominated flame retardants (NBFRs). LÄS MER

7. 25. The in vivo metabolism of Benzo(a)pyrene studied by chromatography in combination with mass spectrometry

   Författare :Yang Yang; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Polycyclic aromatic hydrocarbons (PAHs) constitute a large class of chemicals with widespread occurrence in the environment. It is essentially impossible to avoid exposure to these substances on a daily basis. LÄS MER