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dc.contributor.authorMjøs, Svein Areeng
dc.date.accessioned2006-12-19T21:28:12Z
dc.date.available2006-12-19T21:28:12Z
dc.date.issued2006-11-10eng
dc.identifier.issn82-308-0260-2 (print version)eng
dc.identifier.urihttp://hdl.handle.net/1956/2017
dc.description.abstractThe purpose of this work has been to develop tools for fatty acid identification, with special emphasis on poly-unsaturated fatty acids and trans fatty acids. The work is based on application of gas chromatography with mass spectrometric detection and the fatty acids are analysed as fatty acid methyl esters (FAME). Various multivariate analytical techniques are applied as tools for interpretation of both chromatographic and spectral information. The ten papers are divided into five subsections with the following topics: Identification of FAME from shifts in retention indices: Papers I and II describe methods for partial identification of fatty acid structure from shifts in retention indices. These methods will basically provide information on the polarity (number of double bonds) and the chain lengths of the fatty acids. The procedure is not restricted to any particular class of fatty acids and may also be used to exclude compounds that are not fatty acids. Two-dimensional fatty acid retention indices (2D-FARI) are introduced in Paper II. Application to trans isomers: Papers III and IV are about trans isomers of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Paper III provides data about chromatographic properties of the trans isomers of EPA and DHA, which can be applied both for identification purposes and for optimisation of chromatographic parameters. A practical application of the data is shown in Paper IV. Prediction of equivalent chain lengths: Papers V and VI describe methods for prediction of equivalent chain lengths (ECL), which is the retention indices commonly applied for fatty acids. Paper V is restricted to polyunsaturated fatty acids with methylene-interrupted double bond systems. Paper VI is not restricted to a particular class of fatty acids, but 2D-FARI data must be available. Thus, the two procedures are complementary methods for ECL predictions. Identification of FAME from mass spectra: Paper VII and VIII are about multivariate analysis of mass spectra of FAME. In Paper VII it is shown that trans isomerism in certain positions has significant influence on the mass spectra of polyunsaturated fatty acids. In Paper VIIi it is shown that the number of double bonds in polyunsaturated fatty acids can be determined from selected ions in the mass spectra. Deconvolution of overlapping chromatographic peaks: Papers IX and X are about techniques for deconvolution of overlapping FAME peaks. Transformations for reduction of noise in the mass spectra were introduced in Paper IX. The transformations and the information from Paper VII about differences in the mass spectra caused by trans geometry were utilised for deconcvolution of overlapping chromatographic peaks of trans isomers in Paper X. Although the focus in this paper is basically on the quantification of the isomers, deconvolution of overlapping peaks has relevance also for the identification of the analytes because spectra and accurate retention times of the compounds are also provided.en
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dc.language.isoengeng
dc.publisherThe University of Bergeneng
dc.relation.haspartPaper I: ournal of Chromatography A 1015(1-2), Mjøs, S.A., Identification of fatty acids in gas chromatography by application of different temperature and pressure programs on a single capillary column, pp. 151–161. Copyright 2003 Elsevier.eng
dc.relation.haspartPaper II: Journal of Chromatography A 1061(2), Mjøs, S.A.,Two-dimensional fatty acid retention indices, pp. 201–209. Copyright 2004 Elsevier.eng
dc.relation.haspartPaper III: ournal of Chromatography A 1100(2), Mjøs, S.A., Properties of trans isomers of eicosapentaenoic acid and eicosahexaenoic acid methyl esters on cyanopropyl stationary phases, pp. 185–192. Copyright 2005 Elsevier. Published version available at: <a href="http://dx.doi.org/10.1016/j.chroma.2005.09.079"target=_blank>http://dx.doi.org/10.1016/j.chroma.2005.09.079</a>eng
dc.relation.haspartPaper IV: European Journal of Lipid Science and Technology 108(4), Mjøs, S.A.; Meier, S.; Grahl-Nielsen, O., Geometrical isomerisation of double bonds in acid catalysed preparation of fatty acid methyl esters, pp. 315–322. Copyright 2006 John Wiley & Sons, Inc. Fulltext not available due to publisher restrictions. Published version available at: <a href="http://dx.doi.org/10.1002/ejlt.200500298"target=_blank>http://dx.doi.org/10.1002/ejlt.200500298</a>eng
dc.relation.haspartPaper V: Journal of Chromatography A 1110(1-2), Mjøs, S.A.; Grahl-Nielsen, O., Prediction of gas chromatographic retention of polyunsaturated fatty acid methyl esters, pp. 171–180. Copyright 2006 Elsevier. Published version available at: <a href="http://dx.doi.org/10.1016/j.chroma.2006.01.092"target=_blank>http://dx.doi.org/10.1016/j.chroma.2006.01.092</a>eng
dc.relation.haspartPaper VI: Journal of Chromatography A 1122(1-2) , Mjøs, S.A., Prediction of equivalent chain lengths from two-dimensional fatty acid retention indices, pp. 249–254. Copyright 2006 Elsevier. Published version available at: <a href="http://dx.doi.org/10.1016/j.chroma.2006.04.067"target=_blank>http://dx.doi.org/10.1016/j.chroma.2006.04.067</a>eng
dc.relation.haspartPaper VII: European Journal of Lipid Science and Technology 105(3-4), Mjøs, S.A.; Pettersen, J., Determination of trans double bonds in polyunsaturated fatty acid methyl esters from their electron impact mass spectra, pp.156–164. Copyright 2003 John Wiley & Sons, Inc. Fulltext not available due to publisher restrictions. Published version available at: <a href="http://dx.doi.org/10.1002/ejlt.200390031"target=_blank>http://dx.doi.org/10.1002/ejlt.200390031</a>eng
dc.relation.haspartPaper VIII: European Journal of Lipid Science and Technology 106(8), Mjøs, S.A., The prediction of fatty acid structure from selected ions in electron impact mass spectra of fatty acid methyl esters, pp 550–560. Copyright 2004 John Wiley & Sons, Inc. Fulltext not available due to publisher restrictions. Published version available at: <a href="http://dx.doi.org/10.1002/ejlt.200401013"target=_blank>http://dx.doi.org/10.1002/ejlt.200401013</a>eng
dc.relation.haspartPaper IX: Analytica Chimica Acta 488(2), Mjøs, S.A., Spectral transformations for deconvolution methods applied on gas chromatography–mass spectrometry data, pp. 231–241. Copyright 2003 Elsevier. Published version available at: <a href"=http://dx.doi.org/10.1016/S0003-2670(03)00679-2"target=_blank>http://dx.doi.org/10.1016/S0003-2670(03)00679-2>/a>eng
dc.relation.haspartPaper X: European Journal of Lipid Science and Technology 106(5), Mjøs, S.A., Quantification of linolenic acid isomers by gas chromatography–mass spectrometry and deconvolution of overlapping chromatographic peaks, pp. 307–318. Copyright 2004 John Wiley & Sons, Inc. Fulltext not available due to publisher restrictions. Published version available at: <a href="http://dx.doi.org/10.1002/ejlt.200300909"target=_blank>http://dx.doi.org/10.1002/ejlt.200300909</a>eng
dc.titleInterpretation of chromatographic and mass spectrometric data from analyses of fatty acid methyl esters Application of multivariate methodseng
dc.typeDoctoral thesiseng
dc.subject.nsiVDP::Matematikk og Naturvitenskap: 400::Kjemi: 440nob
dcterms.hasParthttp://dx.doi.org/10.1016/j.chroma.2005.09.079
dcterms.hasParthttp://dx.doi.org/10.1002/ejlt.200500298
dcterms.hasParthttp://dx.doi.org/10.1016/j.chroma.2006.01.092
dcterms.hasParthttp://dx.doi.org/10.1016/j.chroma.2006.04.067
dcterms.hasParthttp://dx.doi.org/10.1002/ejlt.200390031
dcterms.hasParthttp://dx.doi.org/10.1002/ejlt.200401013
dcterms.hasParthttp://dx.doi.org/10.1002/ejlt.200300909


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