title: Analytical approach for the determination of steroid profile of humans by gas chromatography isotope ratio mass spectrometry aimed at distinguishing between endogenous and exogenous steroids.
abstract: The contamination of commonly used supplements by unknown steroids as well as their metabolites (parent compounds) become a challenge for the analytical laboratories. Although the determination of steroids profile is not trivial because of the complex matrix and low concentration of single compound, one of the most difficult current problem is to distinguish, during analytical procedure, endogenous androgens such as testosterone, dehydrotestosterone or dehydroepiandrosterone from their synthetic equivalents. The aim of this work was to develop and validate an analytical procedure for determination of the steroid profile in human urine by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) toward distinguishing between endogenous and exogenous steroids. Beside the optimization of the experimental parameters for gas chromatography separation and mass spectrometry, attention was focused on urine sample preparation. Using an optimized sample preparation protocol it was possible to achieve better chromatographic resolutions and better sensitivity enabling the determination of 5 steroids, androsterone, etiocholanolone, testosterone, 5-androstandiol, 11-hydroxyandrdostane, pregnandiol, with the expanded uncertainty (k=2) below 1‰. This enable to evaluate the significant shift of the δ(13)C/(12)C [‰] values for each of examined steroids (excluding ERC). The analytical protocol described in this work was successfully used for the confirmation of positive founding urine by evaluation T/E ratio after GC/C/IRMS analysis.
authors.affiliation: Faculty of Chemistry, Biological and Chemical Research Center, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland. Electronic address: ebulska@chem.uw.edu.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Bulska
authors.affiliation: Department of Anti-Doping Research, Institute of Sport, Trylogii 2/16, 01-982 Warsaw, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Gorczyca
authors.affiliation: Faculty of Chemistry, Biological and Chemical Research Center, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Zalewska
authors.affiliation: Department of Anti-Doping Research, Institute of Sport, Trylogii 2/16, 01-982 Warsaw, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pokrywka
authors.affiliation: Department of Anti-Doping Research, Institute of Sport, Trylogii 2/16, 01-982 Warsaw, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Kwiatkowska
mesh_terms: D000328:Adult; D045930:Anabolic Agents / Q000032:analysis / Q000652:urine*; D002247:Carbon Isotopes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D008297:Male; D013256:Steroids / Q000032:analysis / Q000652:urine*
chemical_list: D045930:Anabolic Agents; D002247:Carbon Isotopes; D013256:Steroids
keywords: Anabolic androgenic steroids; Gas chromatography isotope ratio mass spectroscopy; Isotopic ratio mass spectrometry; Testosterone; Urine sample preparation