About the Authors

Maonian Xu

Affiliation Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland

Starri Heidmarsson

Affiliation Akureyri Division, Icelandic Institute of Natural History, Akureyri, Iceland

Margret Thorsteinsdottir

Affiliations Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland, ArcticMass, Reykjavik, Iceland

Finnur F. Eiriksson

Affiliations Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland, ArcticMass, Reykjavik, Iceland

Sesselja Omarsdottir

Affiliation Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland

Elin S. Olafsdottir

elinsol@hi.is

Affiliation Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland

Competing Interests

We have the following interests: Margrét Thorsteinsdottir and Finnur Freyr Eiriksson are employed by Arctic Mass. Arctic Mass had the sole role of providing access to instruments (mass spectrometrers) used in this study. There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Author Contributions

Conceptualization: MX SH MT SO ESO. Data curation: MX SH MT FFE. Formal analysis: MX SH FFE. Funding acquisition: MX SH MT SO ESO. Investigation: MX SH FFE. Methodology: MX SH MT FFE SO ESO. Project administration: SH MT SO ESO. Resources: SH MT FFE SO ESO. Software: MX MT FFE. Supervision: SH MT SO ESO. Validation: MX SH MT FFE. Visualization: MX SH MT FFE SO ESO. Writing – original draft: MX. Writing – review & editing: MX SH MT FFE SO ESO.