Universität zu Köln

Piper, Thomas ORCID: 0000-0002-7462-6693 and Thevis, Mario (2017). Applications of Isotope Ratio Mass Spectrometry in Sports Drug Testing Accounting for Isotope Fractionation in Analysis of Biological Samples. In: Methods in Enzymology, S. 403 - 433. SAN DIEGO: ELSEVIER ACADEMIC PRESS INC. ISBN 978-0-12-812273-0

Full text not available from this repository.

Abstract

The misuse of anabolic-androgenic steroids (AAS) in sports aiming at enhancing athletic performance has been a challenging matter for doping control laboratories for decades. While the presence of a xenobiotic AAS or its metabolite(s) in human urine immediately represents an antidoping rule violation, the detection of the misuse of endogenous steroids such as testosterone necessitates comparably complex procedures. Concentration thresholds and diagnostic analyte ratios computed from urinary steroid concentrations of, e.g., testosterone and epitestosterone have aided identifying suspicious doping control samples in the past. These ratios can however also be affected by confounding factors and are therefore not sufficient to prove illicit steroid administrations. Here, carbon and, in rare cases, hydrogen isotope ratio mass spectrometry (IRMS) has become an indispensable tool. Importantly, the isotopic signatures of pharmaceutical steroid preparations commonly differ slightly but significantly from those found with endogenously produced steroids. By comparing the isotope ratios of endogenous reference compounds like pregnanediol to that of testosterone and its metabolites, the unambiguous identification of the urinary steroids' origin is accomplished. Due to the complex urinary matrix, several steps in sample preparation are inevitable as pure analyte peaks are a prerequisite for valid IRMS determinations. The sample cleanup encompasses steps such as solid phase or liquid-liquid extraction that are presumably not accompanied by isotopic fractionation processes, as well as more critical steps like enzymatic hydrolysis, high-performance liquid chromatography fractionation, and derivatization of analytes. In order to exclude any bias of the analytical results, each step of the analytical procedure is optimized and validated to exclude, or at least result in constant, isotopic fractionation. These efforts are explained in detail.

Item Type:	Book Section, Proceedings Item or annotation in a legal commentary
Creators:	Creators Email ORCID ORCID Put Code Piper, Thomas UNSPECIFIED orcid.org/0000-0002-7462-6693 UNSPECIFIED Thevis, Mario UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-245372
DOI:	10.1016/bs.mie.2017.07.013
Title of Book:	Methods in Enzymology
Series Name:	Methods Enzymol.
Volume:	596
Page Range:	S. 403 - 433
Date:	2017
Publisher:	ELSEVIER ACADEMIC PRESS INC
Place of Publication:	SAN DIEGO
ISSN:	0076-6879
ISBN:	978-0-12-812273-0
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ENDOGENOUS URINARY STEROIDS; APPROVED RECOMMENDATION 1987; DOPING CONTROL; C-13/C-12 RATIOS; REFERENCE VALUES; REFERENCE-POPULATION; CARBON; TESTOSTERONE; DERIVATIZATION; INDIVIDUALS Multiple languages Biochemical Research Methods; Biochemistry & Molecular Biology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/24537