Sökning: "stationary phase"

Visar resultat 11 - 15 av 182 avhandlingar innehållade orden stationary phase.

  1. 11. Immobilized stationary phases for capillary gas chromatography

    Författare :Jan Buijten; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Capillary gas chromatography columns coated with silicone gums as stationary phases proved to have a higher thermal stability than columns coated with silicone oils. The temperature stability of a stationary phase film can, however, be further increased when the phase is, in situ, immobilized either by polymerization of the silicone or by freeradical cross-linking. LÄS MER

  3. 12. Development and improvement of methods for characterization of HPLC stationary phases

    Författare :Torgny Undin; Torgny Fornstedt; Jörgen Samuelsson; Anders Törncrona; Johan Ekeroth; Douglas Westerlund; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Adsorption isotherms; Elution by characteristic points; Inflection points; Single component adsorption; Elution by characteristic points method; Slope data; ECP-slope method; Adsorption; Adsorption energy distribution; Adsorption isotherms; AED; Characterization of adsorption processes; Chromatographic analysis; Chromatography; Hydrophobic-subtraction method HSM ; Hydrophobicity; Linear methods; Linear Models; Liquid chromatography; metoprolol; Non-linear methods; Nonlinear methods; phenol; priority journal; propranolol; Retention mechanism; reversed phase liquid chromatography; Solvation; Subtraction method; Thermodynamics; Chemistry with specialization in Surface Biotechnology; Kemi med inriktning mot ytbioteknik;

    Sammanfattning : High Performance Liquid Chromatography (HPLC) is a widely used tech-nique both for detecting and purifying substances in academy and in the industry. In order to facilitate the use of, and knowledge in HPLC, character-ization of stationary phases is of utmost importance. LÄS MER

  4. 13. Development and Investigations of Novel Sample Preparation Techniques : Electrochemical Extraction and Evaluation of Miniaturized Analytical Devices Coupled to Mass Spectrometry

    Författare :Gustav Liljegren; Leif Nyholm; Jean Pettersson; Per Sjöberg; Ari Ivaska; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Analytical chemistry; Electrochemical extraction; Solid-phase microextraction; Solid-phase extraction; Microchip; Mass spectrometry; Polypyrrole; Pressurized-fluid extraction; Preconcentration; Electrospray ionization; Analytisk kemi; Analytical chemistry; Analytisk kemi;

    Sammanfattning : Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phase extractions have been studied in combination with different detection techniques. LÄS MER

  5. 14. Liquid Chromatography-Mass Spectrometry as a Tool for Drug Metabolite Identification in Biological Fluids : With Application to Ketobemidone

    Författare :Ingela Sundström; Per Andrén; Douglas Westerlund; Monika Johansson; Uppsala universitet; []
    Nyckelord :Analytical chemistry; LC-MS MS; accurate mass measurement; drug metabolites; microdialysate; brain; fluorinated stationary phase; phenylboronic acid; retention mechanism; Analytisk kemi;

    Sammanfattning : Electrospray ionization (ESI) mass spectrometry (MS) in combination with liquid chromatography (LC) is an excellent tool for the identification of drug metabolites. Utilizing this hyphenated technique in combination with proper sample pretreatment, the metabolic pathways of the analgesic drug ketobemidone were investigated in human urine and rat microdialysate from blood and brain. LÄS MER

  7. 15. The Non-Linear Instantaneous Least Squares Approach to Signal Parameter Estimation

    Författare :Jakob Ängeby; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aliasing; polynomial-phase signals; synthetic aperture radar auto-focusing; non-linear least squares; time-frequency estimation; estimation theory; non-stationary processes; non-uniform sampling;

    Sammanfattning : Estimation of parameters of non-stationary signals observed in noise is a challenging and difficult task, motivated by applications such as radar and mobile tele-communication. Here, a novel method for signal parameter estimation named the Non-linear Instantaneous Least Squares (NILS) approach is presented, which can be applied to linear and non-linear signals, and to both uniformly and non-uniformly sampled data. LÄS MER