Sökning: "LC-MS"

Visar resultat 11 - 15 av 197 avhandlingar innehållade ordet LC-MS.

1. 11. Isocyanates - methodology for gas and particle generation, sampling and detection

   Författare :Daniel Gylestam; Marianne Dalene; Gunnar Skarping; Daniel Karlsson; Dhimiter Bello; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Isocyanate; PUR; Dry sampler; PTR-MS; Transfer line; PPE; Environmental Chamber; Respirable Particles; Denuder Impactor; Aerosol; Particles; Impinger; air sampling; LC-MS; di-n-butylamine; DBA; ICA; MIC; HDI; TDI; IPDI; MDI; Occupational Exposure; Exposure; Occupational Health; Analytical Chemistry; analytisk kemi;

   Sammanfattning : Isocyanates are mainly used in the industry for the production of polyurethane (PUR) plastics. Workers are at risk of being exposed during the manufacturing of PUR. During thermal degradation of PUR, isocyanates are released and workers involved in hot work such as fire-fighting, welding etc. may also be exposed. LÄS MER

3. 12. 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

4. 13. 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

5. 14. Metabolomics, body composition and fracture

   Författare :Rui Zheng; Karl Michaëlsson; Harri Sievänen; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Metabolomics; LC-MS; sample quality; cohort; body composition; fracture; Medicinsk vetenskap; Medical Science; Bioinformatics; Bioinformatik; Epidemiologi; Epidemiology; Orthopaedics; Ortopedi; Kemi med inriktning mot analytisk kemi; Chemistry with specialization in Analytical Chemistry;

   Sammanfattning : In this thesis, I evaluated the impact of pre-centrifugation sample management on the plasma metabolome, providing verification for the protocol used in a study where I applied metabolomics to better understand the role of body composition in fracture occurrence using a large population-based cohort.  In paper 1, I applied untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics analysis to plasma samples (n = 471) from healthy donors to predict and evaluate the effect of pre-centrifugation temperature and delay time on metabolomics data using a combination of random forest and generalized linear models. LÄS MER

7. 15. Omics Data Analysis of Complex Diseases and Traits

   Författare :Saman Hosseini Ashtiani; Arne Elofsson; Dirk Repsilber; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Omics data; RNA-seq; Microarrays; Metabolomics; Network analysis; Psoriasis; E. coli; Hip osteoporosis; Lung adenocarcinoma; Spearman s correlation coefficient; LC-MS; PCA; DEG; PPI; biokemi med inriktning mot bioinformatik; Biochemistry towards Bioinformatics;

   Sammanfattning : Following the advent of the high-throughput techniques for producing massive omics data, new possibilities and challenges have also emerged in different fields of biology and medicine. Dealing with such data on different scales with different scopes such as genomics, transcriptomics, proteomics and metabolomics, demands appropriate data collection, preprocessing, statistical analysis, interpretation and visualization. LÄS MER