Browsing by Subject "GC-MS"
Now showing items 1-7 of 7
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(2010)3-Chloro-1,2-propanediol (3-MCPD) and its esterified forms are food-borne contaminants. The chemical properties of fatty acid esters of 3-MCPD and their formation in foodstuffs as well as the analytical methods used to detect them were reviewed. The aim of the experimental work was to compare the analytical methods used to detect 3- MCPD esters and to obtain a method for detection of 3-MCPD fatty acid esters in Finnish Food Safety Authority (EVIRA). Synthesised 3-MCPD palmitate esters and palm oil samples were used to detect differences between the methods. Decomposition of 3-MCPD during hydrolysis with sodium methoxide was studied as well as the formation of excess 3- MCPD in palm oil samples during acid hydrolysis. 3-MCPD fatty acid esters were determined as free 3-MCPD by GC-MS after hydrolysis and derivatisation with phenylboronic acid. Free 3-MCPD was cleaved from 3-MCPD esters using acidic hydrolysis with sulphuric acid and methanol or transesterification with sodium methoxide. The amount of 3-MCPD obtained after the hydrolysis of synthesised 3-MCPD esters with sodium methoxide was only 45 % of that obtained after acid hydrolysis. There was a statistical difference between the means at a 95 % level of significance. The formation of excess 3-MCPD during acid hydrolysis was not proven from the results obtained from the palm oil samples. Results showed the opposite, as the amount of 3-MCPD obtained was larger after hydrolysis with sodium methoxide. The precision of the results was poor possibly due to a large systematic error and should be renewed in the future. The results showed there is a significant difference between the two methods of hydrolysis and that the choice between the methods can influence the recovery of the 3-MCPD esters.
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(2021)Tässä pro gradu -tutkielmassa keskitytään Itämereen upotettuihin arseenia sisältäviin kemiallisiin taisteluaineisiin ja niiden analysoinnissa käytettäviin erilaisiin analyysimenetelmiin ja erilaisiin näytematriiseihin. Analyysimenetelmät ovat pääosassa olleet kromatografisia ja massaspektrometrisiä menetelmiä. Tutkielmassa syvennytään lisäksi aseiden upotusalueisiin sekä käydään läpi hieman taustatietoa yhdisteistä ja historiaa aseiden upottamisesta. Pro gradussa tarkastellaan lisäksi upotettujen kemiallisten aseiden toksisuutta ja mahdollisia vaikutuksia ympäristöön ja eliöihin, sekä myös upotettujen aseiden mahdollista riskiä ihmiselle. Tutkielman loppuun sijoittuva kokeellinen osio sisältää VERIFINillä tehdyn menetelmän kehityksen difenyyliarsiinihapon glutationikonjugaatin määrittämiseksi turskan sapesta. Kokeellinen osuus sisältää menetelmän validoinnin sekä varsinaisten upotusaluenäytteiden analysoinnin liittyen DAIMON-projektiin.
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(2009)Methylation analysis by Ciucanu and Kerek (1984) and Hakomori (1964) and the meaning of circumstances in the reaction, reaction parameters and structure of the sample were reviewed in this study. The experimental work consisted of methylation analysis of glucose, cellobiose, isomaltose, pullulan, commercial dextran and dextrans produced by lactic acid bacteria Weissella confusa and Leuconostoc citreum. The success of the methylation was controlled using the IR-method. Methylated samples were treated by methanolysis and acid hydrolysis. The structure analyses were carried out with GC-MSspectra. Two different columns: DB-1 and HP-5 were compared in the GC-analysis. Two hours methylation in the ultrasonic bath gave good methylation results. It was easy to control the methylation by IR-method. OH-peak (3400 cm-1) was absent and CH3- peaks (2900 and 2800 cm-1) were high after successful methylation. IR-spectroscopy is a valuable tool to check if methylation has been successful. Samples could be remethylated before hydrolysis and derivation if necessary. After methanolysis there were ?- and ?-pyranose forms from each methylated monosaccharides. Due to reduction after the acid hydrolysis method, there was only one methylated form from each product. The structures of glucose, cellobiose, isomaltose and pullulan were solved by both hydrolysis methods. Recovery of these samples was good but the deviation was large. The structure of commercial dextran and dextran produced by W. confusa were solved by methanolysis method and partly by acid hydrolysis method. Recovery of these samples was poor. The methylation succeeded only in one of the dextran samples produced by L. citreum. The methylation analysis of dextrans could be developed in the future by increasing the temperature and the time of mixing and by adding some glycerol.
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(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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(2018)The aim of this study was to determine the chemical hazards associated with the packaging materials of liquid packaging board with polyethylene coating on both sides, and if these chemical hazards would transfer to the liquid packaging board and to milk packaged in it. Consumers’ exposure to chemical hazards resulting from the packaging materials of the liquid packaging board used in the packaging of milk was assessed. Additionally, the process of safety assessment of new packaging materials of liquid packaging board was developed and described. A multinational manufacturer of food contact materials bears a great responsibility for the consumer safety and conformance of its products which is why conducting this study was important. A core made of recycled fibre and a tape used in the packaging of liquid packaging board were assessed for their chemical risk in this study. The core consists of adhesives and core board made of recycled fibre. Adhesive tapes consist of backing material and adhesive. Sometimes a primer is used between the backing material and adhesive. The chemical composition and potential sources of contamination were discussed in the literary review. Non-Intentionally Added Substances (NIAS) and substances known to cause alterations in the sensory properties of liquid packaging board and food in adhesive tapes and core board were analysed. Additionally, non-targeted screening methods were employed to detect unpredicted NIAS in the packaging materials, liquid packaging board and a food simulant for milk. The concentrations of NIAS were compared with specific migration limits in the European Commission Regulation (EU) 10/2011 on plastic materials and articles intended to come into contact with food. They were also compared with the values of acceptable and tolerable daily intakes if provided by the European Food Safety Authority (EFSA). The analytical methods that were used for qualitative and quantitative analyses were GC-MS and GC-FID. Predicted and unpredicted NIAS were detected from the packaging materials using the chosen methods. Some of the substances were found to transfer to liquid packaging board and to the food simulant. The migration to the food simulant was not be analysed for some of the NIAS. Additional information on the transfer of these substances to food is still needed. Substances for which adequate toxicological information was available did not pose a threat to consumer safety based on the exposure assessment. Furthermore, a process for the risk assessment of new packaging materials was successfully developed.
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(2019)Today it is desirable to utilise and reproductive sidestream materials from the industry. The food industry generates lot of sidestream waste which could be utilised in various products. Grain hulls are one example. The aim of this work was to study the structure and chemical features of sidestream oat and barley hulls from the industry. Furthermore, the potential to use hull fractions with pulp to produce kraft paper was examined. The grain structure and chemical features of oat and barley have been studied extensively in the food industry but hulls barely at all. The intention was to study lipids, hemicellulose sugars and lignins. From the perspective of paper production, it was important to examine hulls fibres (anatomy), fibre separation and fibre wall fibrillation. Kraft paper must possess specific mechanical properties. Sufficient fibrillation and fibre network of the plant fibres renders paper durable. The hull fibres were examined with a light microscope. The hulls were macerated before microscopy. Compounds, lipids, organic acids and sugars were extracted with hexane and acetone in the Accelerated Solvent Extraction. The samples were analysed with gas chromatography-mass spectrometry. The hemicellulose sugars of the hulls were isolated with methanolysis and analysed with a gas chromatography-flame ionization detector. The hull lignins were defined with pyrolysis-gas chromatography-mass spectrometry. The other compounds of the samples were extracted with acetone by Accelerated Solvent Extraction before pyrolysis determination. The oat and barley hulls were milled with a disc refiner and added to the softwood (pine) pulp in a Valley hollander beater. The pulp was milled for 90 min and the pulp filtration was measured with a Schopper-Riegler freenes tester. Also, water retention value was calculated. Sheets of paper were made with a conventional sheet mould. The aim grammage of the paper sheets was 60 g/m². The mechanical, physical and optical properties of the paper sheets were measured. The properties measured were thickness, density, surface smoothness/roughness, air permeability, opacity, light scattering, light absorption, brightness, tensile strength, breaking strength, elongation, bursting strength and tearing strength. Half of the paper sheets were calandered. The chemical properties of oat and barley hulls did not differ significantly from each other. The same hemicellulose sugars were found in the hulls of both grains, however more mannose and arabinose were found in oat hulls. The hulls of both grains had almost the same total hemicellulose quantity. The quantity and quality of lignins were also similar in both grain hulls. Guaiacyl lignin was dominant in both hulls. Minor differences in hemicellulose sugars does not have an impact on paper production. The hull fibres were very similar in microscopic examination, but oat hulls were somewhat longer than barley hulls. These differences did not impact the separation of fibres, the fibrillation of fibre wall or paper making. Oat hulls were harder, which became most apparent in the calandering and appearance of the sheets. Barley hulls were darker but the mechanical and physical properties of the grain hull paper sheets were quite similar. The hull fractions amount in the pulp (10% or 20%) did not significantly impact the results. The milled hull fractions were not distributed evenly in the sheets, the fibres did not separate properly and no internal or external fibrillation occurred. As mentioned before, the sheets were not homogeneous and the standard deviation of the sheet properties were partly significant. Adding the hull fractions to the pulp was successful and the milled hull fractions did not fall off the sheets. Calandered sheets were smooth and glossy. Moreover, the sheets were visually pleasing. This study indicated that it is possible to use hull fractions for paper and kraft paper production. The paper mostly met the same quality requirements as commercial paper. More research is needed for further optimisation. More research into the chemical properties of oat and barley hulls is also needed, because of the hulls of both grains contain antioxidant components and could provide more information about advanced fibre separation and fibre wall fibrillation.
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(2022)Triglyseridimatriisit sisältävät käsitteenä kaikki lipidimatriisit, kuten eläinrasvat ja kasviöljyt. Triglyseridien lisäksi nämä lipidimatriisit voivat sisältää myös muita heteroatomeja sisältäviä yhdisteitä kuten esimerkiksi typpi- tai happiyhdisteitä. Rasvoja ja öljyjä voidaan käyttää elintarviketeollisuuden lisäksi myös polttoaineteollisuudessa esimerkiksi rasvahappojen metyyliestereistä koostuvan biodieselin tai hiilivedyistä koostuvan uusiutuvan dieselin tuotantoon. Tässä kirjallisuuskatsauksessa esitellään erilaisia uusiutuvien polttoaineiden valmistukseen yleisesti käytettyjä triglyseridimatriiseja sekä niiden sisältämiä yhdisteluokkia, ja perehdytään näiden analysointiin käytettäviin kvalitatiivisiin ja kvantitatiivisiin eristys- ja analyysimenetelmiin. Työssä esitellään useita eläinrasva- ja kasviöljymatriiseja sekä niissä yleisimmin esiintyviä heteroatomeja sisältäviä yhdisteryhmiä. Yhdisteiden eristykseen käytettävistä menetelmistä esitellään neste-nesteuutto, kiinteäfaasiuutto ja saippuointi, ja vastaavasti analyysimenetelmistä käsitellään nestekromatografia (LC), kaasukromatografia (GC) ja massaspektrometria (MS). Triglyseridimatriisien sisältämien heteroatomeja sisältävien epäpuhtauksien ja niiden pitoisuuksien analysointi on tärkeää, sillä näillä epäpuhtauksilla on ympäristöpäästöjen muodostumisen lisäksi useita negatiivia vaikutuksia esimerkiksi polttoaineen tuotantoon, säilyvyyteen ja toimintakykyyn polttomoottoreissa. Tutkielman kokeellisessa osuudessa validoitiin "Rasvahappoamidien, sterolien ja muiden raskaiden yhdisteiden analysointi öljyistä ja rasvoista kaasukromatografisesti" -menetelmä amideille. Validointi koostui kuudesta osuudesta: lineaarisuudesta, määritysrajan ja toteamisrajan määrityksestä, toistettavuudesta, uusittavuudesta, vaihtelevuudesta sekä takaisinsaantokokeesta. Validointi onnistui pääpiirteittäin hyvin, tulokset olivat luotettavia ja vastasivat odotuksia. Validoidun menetelmän rinnalle kehitettiin myös uuttoon perustuvaa menetelmää saippuoitumattomalle osuudelle rasvoista. Menetelmää testattiin eri uuttoliuottimilla ja menetelmän toistettavuutta kokeiltiin. Menetelmällä saatiin näytteistä eristettyä validoituun menetelmään verrattuna huomattavan paljon enemmän erilaisia yhdisteitä. Menetelmän kehitys jäi kuitenkin kesken, sillä esimerkiksi reaktio-olosuhteiden optimointi ja saantojen kvantitointiin vaadittavan malliyhdisteen löytäminen ovat vielä työn alla.
Now showing items 1-7 of 7