Data treatment for analytical raw data
In instrumental analysis like chromatography or chromatography coupled to mass spectrometry, algorithms for compound identification and quantification are usually applied more or less directly on the raw data. However, much can be done to improve the quality of the data prior to identification and quantification. Development and application of methodologies for noise reduction, deconvolution of overlapping signals, and standardization of spectra are important research activities in this field.
Compound identification based on multivariate methodology
In many cases statistical methods will reveal more information about compound structure than classical interpretation of spectra. In chromatographic analyses the proper use of retention indices may contribute significantly to compound elucidation. Research in this field include interpretation of mass spectra by pattern recognition and regression, modelling of retention indices and combined use of spectral and retention information for identification purposes.
Optimization and validation of analytical methods
Research activities in this area include the use of response surface methodology for optimization of chromatographic resolution, the systematic treatment of chromatographic retention, and studies on the efficiency of extraction methods.
Methodologies described above are applied on analysis of lipids, organic pollutants and volatile organic compounds. Applied techniques are gas chromatography (GC), liquid chromatography (LC), mass spectrometry (MS), and hyphenated techniques like GC-MS and LC-MS.
I am currently teaching the course KJEM/FARM-250 Analytical Chemistry.
Master projects are offered within analytical chemistry and chemometrics and within environmental chemistry.
Projects in analytical chemistry will usually be focused on analysis of lipids using gas chromatography, liquid chromatography or mass spectrometry. Characterization of lipids is important in fields like medicine, nutrition and studies of environmental effects. Data handling by chemometric techniques will be essential in most projects.
Projects in environmental chemistry will be focused on analysis of abundance, effects or properties of organic pollutants using chromatographic and mass spectrometric methodology. Master projects are usually carried out in close cooperation with other research groups in Bergen.
- 2017. High intake of fatty fish, but not of lean fish, improved postprandial glucose regulation and increased the n-3 PUFA content in the leucocyte membrane in healthy overweight adults: A randomised trial. British Journal of Nutrition. 117: 1368-1378. doi: 10.1017/S0007114517001234
- 2017. Lipids of Dietzia sp. A14101. Part II: A study of the dynamics of the release of surface active compounds by Dietzia sp. A14101 into the medium. Chemistry and Physics of Lipids. 208: 31-42. doi: 10.1016/j.chemphyslip.2017.08.007
- 2017. Lipids of Dietzia sp. A14101. Part I: A study of the production dynamics of surface-active compounds. Chemistry and Physics of Lipids. 208: 19-30. doi: 10.1016/j.chemphyslip.2017.08.006
- 2017. Effects of baked and raw salmon fillet on lipids and n-3 PUFAs in serum and tissues in Zucker fa/fa rats. Food & Nutrition Research. 61:133395: 1-12. doi: 10.1080/16546628.2017.1333395
- 2016. Plackett-Burman design and fragmentation studies to assist the 1 comparison of techniques used to extract phospholipids prior to regiospecific characterization by liquid chromatography mass spectrometry. American Journal of Modern Chromatography. 3: 1-22. doi: 10.7726/ajmc.1001
- 2016. Dietary fish protein hydrolysates containing bioactive motifs affect serum and adipose tissue fatty acid compositions, serum lipids, postprandial glucose regulation and growth in obese Zucker fa/fa rats. British Journal of Nutrition. 116: 1336-1345. doi: 10.1017/S0007114516003548
- 2016. Intensive lifestyle intervention provides rapid reduction of serum fatty acid levels in women with severe obesity without lowering omega-3 to unhealthy levels. Clinical Obesity. 6. 259-267. doi: 10.1111/cob.12151
- 2016. Predictive associations between serum fatty acids and lipoproteins in healthy non-obese Norwegians: implications for cardiovascular health. Metabolomics. 12. doi: 10.1007/s11306-015-0886-4
- 2016. Specific metabolites in a Phaeodactylum tricornutum strain isolated from Western Norwegian fjord water. Marine Drugs. 14. 17 pages. doi: 10.3390/md14010009
- 2016. Changes in serum fatty acid and lipoprotein subclass concentrations from prepuberty to adulthood and during aging. Metabolomics. 12:51. 10 pages. doi: 10.1007/s11306-016-0968-y
- 2016. Serum fatty acid and lipoprotein subclass concentrations and their associations in prepubertal healthy Norwegian children. Metabolomics. 12. doi: 10.1007/s11306-016-1020-y
- 2016. Application of gas chromatography/tandem mass spectrometry to determine a wide range of petrogenic alkylated polycyclic aromatic hydrocarbons in biotic samples. Rapid Communications in Mass Spectrometry. 30: 2052-2058. doi: 10.1002/rcm.7688
- 2016. Methylmercury Increases and Eicosapentaenoic Acid Decreases the Relative Amounts of Arachidonic Acid-Containing Phospholipids in Mouse Brain. Lipids. 51: 61-73. doi: 10.1007/s11745-015-4087-8
- 2016. An LC–MS-based lipidomics approach for studying the impact of dietary eicosapentaenoic acid on modulating methylmercury toxicity in mice. Metabolomics. 12:174. doi: 10.1007/s11306-016-1121-7
- 2016. Extension of least squares spectral resolution algorithm to high-resolution lipidomics data. Analytica Chimica Acta. 914: 35-46. doi: 10.1016/j.aca.2016.02.002
- 2015. Variable Number of Tandem Repeats (VNTR) analysis of Flavobacterium psychrophilum from salmonids in Chile and Norway. BMC Veterinary Research. 11:150. doi: 10.1186/s12917-015-0469-7
- 2015. Metabolic markers in blood can separate prostate cancer from benign prostatic hyperplasia. British Journal of Cancer. 113: 1712-1719. doi: 10.1038/bjc.2015.411
- 2015. Fatty acids in bacterium Dietzia sp grown on simple and complex hydrocarbons determined as FAME by GC-MS. Chemistry and Physics of Lipids. 190: 15-26. doi: 10.1016/j.chemphyslip.2015.06.002
- 2015. Data on pigments and long-chain fatty compounds identified in Dietzia sp. A14101 grown on simple and complex hydrocarbons. Data in Brief. 4: 622-629. doi: 10.1016/j.dib.2015.07.022
- 2015. Changes in Serum Fatty Acid Levels During the First Year After Bariatric Surgery. Obesity Surgery. Published ahead of print. doi: 10.1007/s11695-015-1980-4
- 2015. Optimizing the relationship between chromatographic efficiency and retention times in temperature-programmed gas chromatography. Journal of Separation Science. 38: 3014-3027. doi: 10.1002/jssc.201500364
- 2014. Determination of Omega-3 Fatty Acids in Fish Oil Supplements Using Vibrational Spectroscopy and Chemometric Methods. Applied Spectroscopy. 68: 1190-1200. doi: 10.1366/13-07210
- 2014. Transfer of retention patterns in gas chromatography by means of response surface methodology. Journal of Chromatography A. 1332: 64-72. doi: 10.1016/j.chroma.2014.01.039
- 2014. A low dietary intake of cod protein is sufficient to increase growth, improve serum and tissue fatty acid compositions, and lower serum postprandial glucose and fasting non-esterified fatty acid concentrations in obese Zucker fa/fa rats. European Journal of Nutrition. 54: 1151-1160. doi: 10.1007/s00394-014-0793-x
- 2014. Effects of duodenal switch alone or in combination with sleeve gastrectomy on body weight and lipid metabolism in rats. Nutrition and Diabetes. 4. 6 pages. doi: 10.1038/nutd.2014.22
- 2014. Effect of two types of bariatric surgery on the fatty acid profile in serum. The Complexity of obesity proceedings. 1. doi: 10.6084/m9.figshare.1211862
- 2014. Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters. Journal of Chromatography A. 1350: 83-91. doi: 10.1016/j.chroma.2014.05.023
- 2014. Influence of type of raw material on fishmeal physicochemical properties, the extrusion process, starch gelatinization and physical quality of fish feed. Aquaculture Nutrition. 20: 410-420. doi: 10.1111/anu.12093
- 2013. Krill hydrolysate free amino acids responsible for feed intake stimulation in Atlantic salmon (Salmo salar). Aquaculture Nutrition. 19: 47-61. doi: 10.1111/anu.12094
- 2013. Impact of variability in fishmeal physicochemical properties on the extrusion process, starch gelatinization and pellet durability and hardness. Animal Feed Science and Technology. 179: 77-84. doi: 10.1016/j.anifeedsci.2012.10.009
- 2013. A database of chromatographic properties and mass spectra of fatty acid methyl esters from omega-3 products. Journal of Chromatography A. 1299: 94-102. doi: 10.1016/j.chroma.2013.05.056
- 2013. Least squares spectral resolution of liquid chromatography-mass spectrometry data of glycerophospholipids. Journal of Chromatography A. 1280: 23-34. doi: 10.1016/j.chroma.2012.12.070
- 2012. High growth rates in Atlantic salmon (Salmo salar L.) fed 7.5% fish meal in the diet. Micro-, ultra- and nano-filtration of stickwater and effects of different fractions and compounds on pellet quality and fish performance. Aquaculture. 338: 134-146. doi: 10.1016/j.aquaculture.2012.01.017
- 2012. Trans isomers of EPA and DHA in Omega-3 products on the European market. Lipids. 47: 659-667. doi: 10.1007/s11745-012-3672-3
- 2012. Efficiencies of three common lipid extraction methods evaluated by calculating mass balances of the fatty acids. Journal of Food Composition and Analysis. 25: 198-207. doi: 10.1016/j.jfca.2011.08.003
- 2011. Trans Fatty Acid Analyses in Samples of Marine Origin: The Risk of False Positives. Journal of Agricultural and Food Chemistry. 59: 3520-3531. doi: 10.1021/jf104156v
- 2011. Experimental designs for modeling retention patterns and separation efficiency in analysis of fatty acid methyl esters by gas chromatography-mass spectrometry. Journal of Chromatography A. 1218: 6823-6831. doi: 10.1016/j.chroma.2011.07.077
- 2010. The vector of calibration ratios: A simple transfer method for mass spectra. Journal of Chromatography A. 1217: 5986-5994. doi: 10.1016/j.chroma.2010.07.039
- 2009. A Rank annihilation approach to reducing the scan-effect in gas chromatography-mass spectrometry data. Analytica Chimica Acta. 640: 33-39. doi: 10.1016/j.aca.2009.03.011
- 2008. Retention behavior of trans isomers of eicosapentaenoic and docosahexaenoic acid methyl esters on a polyethylene glycol stationary phase. European Journal of Lipid Science and Technology. 110: 547-553. doi: 10.1002/ejlt.200700225
- 2007. Identification of estrogen-like alkylphenols in produced water from offshore oil installations. Marine Environmental Research. 64: 651-655. doi: 10.1016/j.marenvres.2007.07.001
- 2006. Validation of a one-step extraction/methylation method for determination of fatty acids and cholesterol in marine tissues. Journal of Chromatography A. 1104: 291-298. doi: 10.1016/j.chroma.2005.11.045
- 2006. Prediction of equivalent chain lengths from two-dimensional fatty acid retention indices. Journal of Chromatography A. 1122: 249-254. doi: 10.1016/j.chroma.2006.04.067
- 2006. Alkylphenol retention indices. Journal of Chromatography A. 1123: 98-105. doi: 10.1016/j.chroma.2006.05.002
- 2006. Geometrical isomerisation of double bonds in acid catalysed preparation of fatty acid methyl esters. European Journal of Lipid Science and Technology. 108: 315-322. doi: 10.1002/ejlt.200500298
- 2006. Patterns in volatile components over heated fish powders. Food Research International. 39: 190-202. doi: 10.1016/j.foodres.2005.07.006
- 2006. Geometrical isomerisation of EPA and DHA at high temperatures. European Journal of Lipid Science and Technology. 108: 589-597. doi: 10.1002/ejlt.200600055
- 2005. Properties of trans isomers of eicosapentaenoic acid and eicosahexaenoic acid methyl esters on cyanopropyl stationary phases. Journal of Chromatography A. 1100: 185-192. doi: 10.1016/j.chroma.2005.09.079
- 2004. The prediction of fatty acid structure from selected ions in electron impact mass spectra of fatty acid methyl esters. European Journal of Lipid Science and Technology. 106: 550-560. doi: 10.1002/ejlt.200401013
- 2004. Quantification of linolenic acid isomers by gas chromatography-mass spectrometry and deconvolution of overlapping chromatographic peaks. European Journal of Lipid Science and Technology. 106: 307-318. doi: 10.1002/ejlt.200300909
- 2004. Two-dimensional fatty acid retention indices. Journal of Chromatography A. 1061: 201-209. doi: 10.1016/j.chroma.2004.11.025
- 2003. Spectral transformations for deconvolution methods applied on gas chromatography–mass spectrometry data. Analytica Chimica Acta. 488: 231-241. doi: 10.1016/S0003-2670(03)00679-2
- 2003. Identification of fatty acids in gas chromatography by application of different temperature and pressure programs on a single capillary column. Journal of Chromatography A. 1015: 151-161. doi: 10.1016/S0021-9673(03)01240-8
- 2003. Determination of trans double bonds in polyunsaturated fatty acid methyl esters from their electron impact mass spectra. European Journal of Lipid Science and Technology. 105: 156-164. doi: 10.1002/ejlt.200390031
- 2003. A rapid method for the analysis of hydrogenated fats by GC with IR detection. Journal of the American Oil Chemists Society. 80: 839-846. doi: 10.1007/s11746-003-0783-0
- 2015. Fishmeal physicochemical properties – Impact on the fish feed extrusion process, phase transitions and physical pellet quality. University of Bergen.
- 2011. Analyse av transfettsyrer i marine lipider – Risiko for falske positive. Nofima rapportserie. 21/2011. Nofima AS, Tromsø. 5 pages.
- 2007. Flyktige komponenter i tørrfisk. Nofima rapportserie. 26/2007. Nofima AS (tidligere Fiskeriforskning), Tromsø. 20276 pages.
- 2006. Interpretation of chromatographic and mass spectrometric data from analyses of fatty acid methyl esters – Application of multivariate methods.
- 1996. Effekter på fettsyresammensetningen i egg fra atlantisk torsk (Gadus morhua) : bruk av gasskromatografi og multivariate metoder. UiB. 106 pages.
L. Zhang, S.A. Mjøs, S. Meier, O.M. Kvalheim, Y. Liang (2010) The vector of calibration ratios: A simple transfer method for mass spectra. J. Chromatogr. 1217: 5986-5994 [DOI: 10.1016/j.chroma.2010.07.039]
S.A. Mjøs, B. Grung (2009) A rank annihilation approach to reducing the scan-effect in gas chromatography – mass spectrometry data. Anal. Chim. Acta 640: 33-39 [DOI: 10.1016/j.aca.2009.03.011]
S.A. Mjøs (2008) Trans isomers of eicosapentaenoic and docosahexaenoic methyl esters on a polyethylene glycol (PEG) stationary phase. Eur. J. Lipid Sci. Technol. 110: 547-553 [DOI: 10.1002/ejlt.200700225]
S. Boitsov, S.A. Mjøs, S. Meier (2007) Identification of estrogen-like alkylphenols in produced water from offshore oil installations. Marine Environmental Research 64: 651-665 [DOI: 10.1016/j.marenvres.2007.07.001]
S.A. Mjøs (2006) Interpretation of chromatographic and mass spectrometric data from analyses of fatty acid methyl esters – Application of multivariate methods, PhD thesis, University of Bergen [ISSN: 82-308-0260-2]
S.A. Mjøs, M. Solvang (2006) Geometrical isomerisation of EPA and DHA at high temperatures. Eur. J. Lipid Sci. Technol. 108: 589-597 [DOI: 10.1002/ejlt.200600055]
S.A. Mjøs (2006) Prediction of equivalent chain lengths from two-dimensional fatty acid retention indices. J. Chromatography A. 1122: 249-254 [DOI: 10.1016/j.chroma.2006.04.067]
S.A. Mjøs, S. Boitsov, S. Meier (2006) Alkylphenol retention indices (APRI). J. Chromatography A. 1123: 98-105 [DOI: 10.1016/j.chroma.2006.05.002].
S.A. Mjøs, O. Grahl-Nielsen (2006) Prediction of gas chromatographic retention of polyunsaturated fatty acid methyl esters. J. Chromatography A. 1110: 171-180 [DOI: 10.1016/j.chroma.2006.01.092]
S.A. Mjøs, S. Meier, O. Grahl-Nielsen, Geometrical isomerisation of double bonds in acid catalysed preparation of fatty acid methyl esters. Eur. J. Lipid Sci. Technol. 108: 315-322 [DOI: 10.1002/ejlt.200500298]
S. Meier, S.A. Mjøs, H. Joenssen, O. Grahl-Nielsen (2006) Validation of a one-step extraction/methylation method for determination of fatty acids and cholesterol in marine tissues. J. Chromatography A. 1104: 291-298 [DOI: 10.1016/j.chroma.2005.11.045]
S.A. Mjøs & M. Solvang (2006) Patterns in volatile components over heated fish powders. Food Research International 39: 190-202 [DOI: 10.1016/j.foodres.2005.07.006]
S.A. Mjøs (2005) Properties of trans isomers of eicosapentaenoic acid and eicosahexaenoic acid methyl esters on cyanopropyl stationary phases. J. Chromatography A. 1100: 185-192 [DOI: 10.1016/j.chroma.2005.09.079]
S.A. Mjøs (2004) Two-dimensional fatty acid retention indices. J. Chromatography A 1061: 201-209 [DOI: 10.1016/j.chroma.2004.11.025]
S.A. Mjøs (2004) The prediction of fatty acid structure from selected ions in electron impact mass spectra of fatty acid methyl esters. Eur. J. Lipid. Sci. Technol. 106: 550-560 [DOI: 10.1002/ejlt.200401013]
S.A. Mjøs (2004) Quantification of linolenic acid isomers by gas chromatography/mass spectrometry and deconvolution of overlapping chromatographic peaks. Eur. J. Lipid Sci. Technol. 106: 307-318 [DOI: 10.1002/ejlt.200300909]
S.A. Mjøs (2003) Identification of fatty acids in gas chromatography by application of different temperature and pressure programs on a single capillary column. J. Chromatography A, 1015: 151-161 [DOI: 10.1016/S0021-9673(03)01240-8]
S.A. Mjøs (2003) Spectral transformations for deconvolution methods applied on gas chromatography-mass spectrometry data. Analytica Chimica Acta 488: 231-241 [DOI: 10.1016/S0003-2670(03)00679-2]
S.A. Mjøs & Pettersen (2003) A rapid method for the analysis of hydrogenated fats by GC with IR detection. J. Am. Oil Chem. Soc. 80: 839-846 [DOI: 10.1007/s11746-003-0783-0]
S.A. Mjøs & J. Pettersen (2003) Determination of trans double bonds in polyunsaturated fatty acid methyl esters from their electron impact mass spectra. Eur. J. Lipid Sci. Technol. 105: 156-164 [DOI: 10.1002/ejlt.200390031]
Nenseter, Østerud, Larsen, Strøm, Bergei, Hewitt, Holven, Hagve, Mjøs, Solvang, Pettersen, Opstvedt, Ose. (2000) Effect on Norwegian fish powder on risk factors for coronary heart disease among hypercholesterolemic individuals. Nutr. Metab. Cardiovasc. Dis. 10: 323-330.