Arsenic-containing fatty acids and hydrocarbons in marine oils - determination using reversed-phase HPLC-ICP-MS and HPLC-qTOF-MS

Veronika Sele; Jens J Sloth; Bjarte Holmelid; Stig Valdersnes; Kasper Skov; Heidi Amlund

doi:10.1016/j.talanta.2013.12.049

Arsenic-containing fatty acids and hydrocarbons in marine oils - determination using reversed-phase HPLC-ICP-MS and HPLC-qTOF-MS

Talanta. 2014 Apr:121:89-96. doi: 10.1016/j.talanta.2013.12.049. Epub 2013 Dec 30.

Authors

Veronika Sele¹, Jens J Sloth², Bjarte Holmelid³, Stig Valdersnes⁴, Kasper Skov⁵, Heidi Amlund⁶

Affiliations

¹ National Institute of Nutrition and Seafood Research, Post Box 2029, Nordnes, N-5817 Bergen, Norway; Institute of Biology, University of Bergen, Post Box 7803, N-5020 Bergen, Norway.
² National Institute of Nutrition and Seafood Research, Post Box 2029, Nordnes, N-5817 Bergen, Norway; National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
³ Department of Chemistry, University of Bergen, Post Box 7803, N-5020 Bergen, Norway.
⁴ National Institute of Nutrition and Seafood Research, Post Box 2029, Nordnes, N-5817 Bergen, Norway.
⁵ National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
⁶ National Institute of Nutrition and Seafood Research, Post Box 2029, Nordnes, N-5817 Bergen, Norway. Electronic address: Heidi.Amlund@nifes.no.

PMID: 24607114
DOI: 10.1016/j.talanta.2013.12.049

Abstract

Arsenolipids are the major arsenic species present in marine oils. Several structures of arsenolipids have been elucidated the last 5 years, demonstrating the chemical complexity of this trace element in the marine environment. Several commercial fish oils and marine oils, ranging in total arsenic concentrations from 1.6 to 12.5 mg kg(-1) oil, were analyzed for arsenolipids using reversed-phase high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The arsenolipids were quantified using three different arsenic-containing calibration standards; dimethylarsinate (DMA), triphenylarsinoxide (Ph₃AsO) and a synthesized arsenic-containing hydrocarbon (AsHC) (dimethylarsinoyl nonadecane; C₂₁H₄₃AsO). The observed variation in signal intensity for arsenic during the gradient elution profile in reversed-phase HPLC was compensated for by determining the time-resolved response factors for the arsenolipids. Isotopes of germanium ((74)Ge) and indium ((115)In) were suited as internal standards for arsenic, and were used for verification of the arsenic signal response factors during the gradient elution. Dimethylarsinate was the most suitable calibration standard for the quantification of arsenolipids, with recoveries between 91% and 104% compared to total arsenic measurements in the same extracts. A range of marine oils was investigated, including oils of several fish species, cod liver and seal, as well as three commercial fish oils. The AsHCs - C₁₇H₃₈AsO, C₁₉H₄₂AsO and C₂₃H₃₈AsO - were identified as the major arsenolipids in the extracts of all oils by HPLC coupled with quadrupole time-of-flight mass spectrometry (qTOF-MS). Minor amounts of two arsenic-containing fatty acids (AsFAs) (C₂₃H₃₈AsO₃ and C₂₄H₃₈AsO₃) were also detected in the oils. The sum of the AsHCs and the AsFAs determined in the present study accounted for 17-42% of the total arsenic in the oils.

Keywords: Arsenic; Arsenolipids; HPLC–ICP-MS; HPLC–qTOF-MS; Marine oils; Speciation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Arsenic / analysis*
Chromatography, High Pressure Liquid / methods*
Fatty Acids / chemistry*
Fish Oils / chemistry*
Hydrocarbons / chemistry*
Mass Spectrometry / methods*

Substances

Fatty Acids
Fish Oils
Hydrocarbons
Arsenic