Related Experiment Video
Updated: May 20, 2026

Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis
Published on: August 15, 2018
Complementary stable carbon isotope ratio and amount of substance measurements in sports anti-doping
Adam T Cawley1, Adrian V George
1Australian Racing Forensic Laboratory, Racing NSW, Kensington, NSW, Australia. acawley@racingnsw.com.au
Abstract:
The detection of steroids originating from synthetic precursors against a background of their chemically identical natural analogues has proven to be a significant challenge for doping control laboratories accredited by the World Anti-Doping Agency (WADA). The complementary application of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) has been demonstrated to provide specific detection of endogenous steroid misuse for improved anti-doping analysis. Markers of synthetically derived steroids are reviewed on the basis of abnormal urinary excretions and low (13)C content. A combinatorial approach is presented for the interpretation of GC-MS and GC-C-IRMS data in the anti-doping context. This methodology can allow all relevant information concerning an individual's metabolism to be assessed in order to make an informed decision with respect to a doping violation.
Related Concept Videos
Mass Spectrometry: Isotope Effect
Isotopes
An element's atomic mass, or weight, is a...
¹³C NMR: ¹H–¹³C Decoupling
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
Radioactive Decay and Radiometric Dating
Chemical Shift: Internal References and Solvent Effects
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
High-Resolution Mass Spectrometry (HRMS)

