title: A novel method for analysing key corticosteroids in polar bear (Ursus maritimus) hair using liquid chromatography tandem mass spectrometry.
abstract: This paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. Such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. We developed a combined pressurized liquid extraction (PLE)-solid phase extraction (SPE) procedure for corticosteroid extraction and clean-up followed by high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. This procedure allows for the simultaneous determination of multiple steroids, which is in contrast to previous polar bear studies based on ELISA techniques. Absolute method recoveries were 81%, 75% and 60% for cortisol, corticosterone and aldosterone, respectively. We applied the developed method on a hair sample pooled from four East Greenland polar bears. Herein cortisol and corticosterone were successfully determined in levels of 0.32±0.02ng/g hair and 0.13±0.02ng/g hair, respectively. Aldosterone was below limit of detection (LOD<0.17ng/g). The cortisol hair concentration found in these East Greenland polar bears was consistent with cortisol levels previously determined in the Southern Hudson Bay and James Bay in Canada using ELISA kits.
authors.affiliation: Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
authors.forename: Johan J
authors.initials: JJ
authors.lastname: Weisser
authors.affiliation: Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Hansen
authors.affiliation: Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
authors.forename: Erland
authors.initials: E
authors.lastname: Björklund
authors.affiliation: Arctic Research Centre (ARC), Department of Bioscience, Aarhus University, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Sonne
authors.affiliation: Arctic Research Centre (ARC), Department of Bioscience, Aarhus University, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Dietz
authors.affiliation: Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address: Bjarne.styrishave@sund.ku.dk.
authors.forename: Bjarne
authors.initials: B
authors.lastname: Styrishave
mesh_terms: D000305:Adrenal Cortex Hormones / Q000032:analysis*; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006197:Hair / Q000737:chemistry*; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry / Q000379:methods*; D001503:Ursidae
chemical_list: D000305:Adrenal Cortex Hormones
keywords: Aldosterone; Corticosterone; Cortisol; Fur; LC–MS/MS; PLE; Polar bear hair; SPE