Method development and analysis of arsenolipids in marine oils
Doctoral thesis
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http://hdl.handle.net/1956/7983Utgivelsesdato
2014-05-19Metadata
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Sammendrag
Arsenic in marine oils is mainly present in the form of lipid-soluble compounds; collectively called arsenolipids. Although total arsenic concentrations in marine oils typically range from 0.2 to 16 mg kg-1 [1-3], knowledge regarding the chemical structures and distribution of arsenolipids in oils is limited. The present work describes the development of analytical methods for the determination of arsenolipids, and their application to marine oil, including fish oil and oil of liver of Northeast Arctic cod (Gadus morhua). In the present work gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) was applied for analysing arsenic-containing hydrocarbons (AsHCs) in fish oil. The AsHCs were extracted into aqueous methanol, and further subjected to solid-phase extraction (SPE) prior to analysis. Reversedphase HPLC-ICP-MS was applied as an analytical technique for analysis of both AsHCs and arsenic-containing fatty acids (AsFAs) in methanol phase of marine oil. The AsHCs and AsFAs were accurately quantified in reversed-phase HPLC-ICP-MS analysis using dimethylarsinate as calibration standard. The molecular structures of the arsenolipids were identified using mass spectrometry. The oils included in the present work contained total arsenic concentrations from 1.6 to 12.5 mg kg-1 oil. Three AsHCs (AsHC-C15, AsHC-C17 and AsHC-C21) were identified as major arsenolipids in all marine oil. Also, two AsFAs (AsFA-C21 and AsFA-C22) were identified as minor arsenolipids in some of the oils. In cod liver, three AsHCs (AsHC-C15, AsHC-C17 and AsFA-C22) and up to five AsFAs (AsFAC15, AsFA-C17a, AsFA-C17b, AsFA-C21 and AsFA-C22) were identified. The present work contributes with data on the presence of arsenolipids, in the form of AsHCs and AsFAs, in a number of marine oils. The developed methods form the basis for future studies on arsenolipids, e.g. the occurrence of arsenolipids in feed and farmed fish.
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Paper I: Veronika Sele, Heidi Amlund, Marc H.G. Berntssen, Jannicke Berntsen, Kasper Skov and Jens J. Sloth. Detection of arsenic-containing hydrocarbons in a range of commercial fish oil by GC-ICPMS analysis. Analytical and Bioanalytical Chemistry, 2013, 405 (15), 5179-5190. The article is not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1007/s00216-013-6925-yPaper II: Veronika Sele, Jens J. Sloth, Bjarte Holmelid, Stig Valdersnes, Kasper Skov and Heidi Amlund. Arsenic-containing fatty acids and hydrocarbons in marine oils – Determination using reversed-phase HPLC–ICP-MS and HPLC–qTOFMS. Talanta: The International Journal of Pure and Applied Analytical Chemistry, 2014, 121, 89-96. The article is not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1016/j.talanta.2013.12.049
Paper III: Veronika Sele, Jens J. Sloth, Kåre Julshamn, Kasper Skov and Heidi Amlund. A study of lipid- and water-soluble arsenic species in liver of Northeast Arctic cod (Gadus morhua) containing high levels of total arsenic. The article is not available in BORA.