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Borden SA, Damer HN, Krogh ET, Gill CG. Direct quantitation and characterization of fatty acids in salmon tissue by condensed phase membrane introduction mass spectrometry (CP-MIMS) using a modified donor phase. Anal Bioanal Chem 2018; 411:291-303. [PMID: 30470916 DOI: 10.1007/s00216-018-1467-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/15/2018] [Accepted: 10/31/2018] [Indexed: 12/15/2022]
Abstract
Existing mass spectrometric methods for the analysis of fatty acids often require derivatization, chromatographic separations, and/or extensive sample preparation. Direct mass spectrometry strategies can avoid these requirements, but may also suffer from poor quantitation and/or lack of sensitivity. Condensed phase-membrane introduction mass spectrometry (CP-MIMS) provides direct quantitative measurements of analytes in complex samples with little or no sample preparation. CP-MIMS uses a semipermeable membrane to transfer neutral, hydrophobic compounds from real-world samples to a mass spectrometer. The results presented utilize aqueous/organic sample solvent (donor) mixtures to allow for the sensitive (pptr) detection of a range of fatty acids. The relative sensitivity across a homologous series of fatty acids is observed to change, favoring short- or long-chain fatty acids, depending on the amount of miscible co-solvent added to the donor phase. Further, lithium acetate added online via the acceptor phase was used in tandem mass spectrometry experiments to determine the location of double bonds in polyunsaturated fatty acids (PUFAs). The method was applied to direct measurements and structural determinations for selected PUFAs in salmon tissue samples. Standard addition was employed to quantify the amount of PUFAs in a variety of salmon samples, yielding 0.27-0.42 and 0.40-0.84 w/w % for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively, for Sockeye and Chinook salmon, in good agreement with the literature. This work presents, to our knowledge, the first use of CP-MIMS for the direct analysis of fatty acids in oily foodstuff samples. Graphical abstract ᅟ.
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Affiliation(s)
- Scott A Borden
- Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, V9R 5S5, Canada.,Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada
| | - Hannah N Damer
- Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, V9R 5S5, Canada
| | - Erik T Krogh
- Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, V9R 5S5, Canada.,Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada
| | - Chris G Gill
- Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, V9R 5S5, Canada. .,Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada. .,Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada. .,Department of Environmental and Occupational Health Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
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