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Browsing by Subject "GC"

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  • Analysis of volatile organic compounds emitted from indoor building materials 
    Heiskanen, Ilmari (2021)
    Interest towards indoor air quality has increased for several decades from human health perspective. In order to evaluate the quality of indoor air in terms of volatile organic compound (VOC) levels, robust analytical procedures and techniques must be used for indoor air VOC measurements. Since indoor building materials are the greatest source of indoor VOC emissions, same kind of procedures must be used for analysis of emission rates from building materials and their surfaces. Theory part of this thesis reviews background of VOCs and human health, legislation and guideline values, common building materials with emissions and used sampling techniques/approaches for indoor air sampling and surface material emission rate sampling & analysis. Discussed sampling techniques include, for example, material emission test chambers, field and laboratory test emission cells, solid phase microextraction (SPME) fibre applications and Radiello passive samplers. Also new innovative approaches are discussed. Used common analysis instruments are Gas Chromatography (GC) with Mass Spectrometer (MS) or Flame Ionization Detector (FID) for VOCs and High-Performance Liquid Chromatography-Ultraviolet/Visible light detector (HPLC-UV/VIS) for carbonyl VOCs (e.g. formaldehyde) after suitable derivatization. Analytical procedures remain highly ISO 16000 standard series orientated even in recent studies. In addition, potential usage of new modern miniaturized sample collection devices SPME Arrow and In-tube extraction (ITEX) used in experimental part of this thesis are discussed as an addition to indoor air and VOC emission studies. The aim of the experimental part of this thesis was to develop calibrations for selected organic nitrogen compounds with SPME Arrow and ITEX sampling techniques and test the calibration with indoor and outdoor samples. A calibration was successfully carried out with SPME Arrow (MCM-41 sorbent), ITEX (MCM-TP sorbent) and ITEX (Polyacrylonitrile (PAN) 10 % sorbent) with permeation system combined with GC-MS for the following selected organic nitrogen compounds: triethylamine, pyridine, isobutyl amine, allylamine, trimethylamine, ethylenediamine, dipropyl amine, hexylamine, 1,3-diaminopropane, 1-methyl-imidazole, N, N-dimethylformamide, 1,2-diaminocyclohexane, 1-nitropropane and formamide. The overall quality of the calibration curves was evaluated, and the calibrations were compared in terms of linear range, relative standard deviation (RSD) % for accepted calibration levels and obtained Limits of Detection (LOD) values. Also, ways to improve the calibrations were discussed. The calibration curves were tested with real indoor and outdoor samples and quantitative, as well as semi-quantitative, results were obtained.
  • Determination of Amino Acids in Foods and Beverages 
    Sillanpää, Meri (2021)
    The literature study of this thesis focuses on the different analytical methods used to analyse amino acids in food and beverage samples. Amino acids are essential organic molecules and their concentrations in foods and beverages constitute, inter alia, the product’s nutritional value, quality, freshness, and flavour. Amino acid analysis of foodstuff has various applications, which exploit several analytical methods. These reviewed methods are founded on academic articles published during the past two decades. This literature review discusses the different sample matrixes, sample preparation methods, ways to derivate analytes, and different separation and detection methods utilized in the recent amino acid studies. The experimental part of this thesis was a modification of L-asparagine and L-aspartic acid test (L-Asp/L-AspAc) in Thermo Fisher Scientific Oy industrial R&D laboratory. An enzymatic photometric method is used to determine L-Asp/L-AspAc amino acids in food samples. The modification process entailed pre-testing of several candidate methods, from which the most suitable one was selected. The feasibility of the chosen test was affirmed before verification and validation of the modified test.
  • Räjähdysaineiden määritys sedimentistä kaasukromatografimassaspektrometrisesti 
    Kuula, Matti (2020)
    Toisen maailmansodan jälkeen Itämereen upotettiin useita tonneja kemiallisia aseita ja niiden mukana myös ammusten sisältämät räjähdysaineet. Kemialliset räjähdysaineet, jotka ovat yleisimpiä räjähteitä, ovat joko yhdisteitä tai niiden seoksia. Pro gradu-tutkielman tarkoitus oli kartoittaa, voisiko taisteluaineanalytiikkaa varten tehtyjä menetelmiä hyödyntää myös räjähdeaineiden tutkimiseksi. Käytetyin analyysimenetelmä taisteluaineanalytiikassa on kaasukromatografi-massaspektrometri ja siksi tässä tutkimuksessa keskitytään siihen, vaikka joillekin räjähdeaineille nestekromatografia voisi olla parempi analyysitekniikka. Tutkielman kokeellisessa osiossa analysoitiin merenpohjassa olevia räjähdysaineita kaasukromatografi-kolmoiskvadrupolimassaspektrometrilla. Nopealla kaasukromatografimenetelmällä voitiin nopeuttaa analyysejä sekä vähentää yhdisteiden hajoamista kromatografisen erottumisen aikana. Tutkimuksessa hyödynnettiin nopeaa kaasukromatografiaa käyttäen kolmoiskvadrupolimassaspektrometriaa ja usean reaktion seurantaa. Näytteensyötössä käytettiin lämpötilaohjelmoitua injektointia. Tutkituista räjähdysaineista kaikki muut paitsi 1,3,5,7-tetranitro-1,3,5,7-tetratsoktaani (HMX) saatiin näkymään. Lisäksi kaasukromatografi-kolmoiskvadrupolimassaspektrometrilla suoritettavia lisätutkimuksia tarvitaan vielä seuraavien räjähteiden, nitroglyseriini (NG), pentaerytritoli tetranitraatti (PETN) ja metyyli-2,4,6-trinitrofenyylinitramiini (Tetryl), luotettavaksi määrittämiseksi.

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