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Development of a sensitive GC-C-IRMS method for the analysis of androgens in doping control

Michaël Polet (UGent) , Wim Van Gansbeke (UGent) and Peter Van Eenoo (UGent)
Author
Organization
Abstract
All doping control laboratories accredited by the World Anti-Doping Agency (WADA) have been confronted with the task to develop analytical methods and establish criteria that allow endogenous steroids to be distinguished from their synthetic copies. It has been known for some time that gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is capable of meeting this challenge by comparison of the 13C/12C ratios of the target compounds with those of endogenous reference compounds that are not affected by the administration of synthetic androgens. Testosterone and/or its main metabolites function as target compounds. Typical endogenous reference compounds include 5β-pregnanediol, 11-ketoetiocholanolone and 11-βhydroxyandrosterone. Synthetic copies are generally derived from stigmasterol and sitosterol; plant sterols obtained from soybean (Glycine max) which have a significantly different carbon isotope composition compared to endogenous steroids. As a consequence, the administration of synthetic analogs is detectable through a change in the carbon isotopic composition of testosterone and its metabolites. GC-C-IRMS however remains a very laborious and expensive technique because one can only determine the 13C/12C ratio of a pure compound. This means that a lot of purification steps have to be conducted and fractionation caused by one of these steps is unacceptable. On top of that, substantial amounts of urine are needed to meet the sensitivity requirements of the IRMS. Because the amount of received urine from an athlete is limited, doping control laboratories have to make their analysis as sensitive as possible so all the required doping tests can be executed. If less urine is consumed, then there is more available for additional tests. In this work we introduce a new type of injection which takes GC-C-IRMS to the next level. With the aid of a programmed temperature vaporizer we were able to increase the sensitivity of the IRMS with a factor of 10 and we drastically reduced the required amount of urine and the limit of detection. All this is achieved without having to change any of the IRMS detection parameters.
Keywords
androgens, doping control, solvent vent injection, GC-C-IRMS

Citation

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MLA
Polet, Michaël, et al. “Development of a Sensitive GC-C-IRMS Method for the Analysis of Androgens in Doping Control.” Benelux Association of Stable Isotope Scientists, Annual Meeting, Abstracts, Cito Arnhem, 2012, pp. 21–21.
APA
Polet, M., Van Gansbeke, W., & Van Eenoo, P. (2012). Development of a sensitive GC-C-IRMS method for the analysis of androgens in doping control. Benelux Association of Stable Isotope Scientists, Annual Meeting, Abstracts, 21–21. Arnhem, Nederland: Cito Arnhem.
Chicago author-date
Polet, Michaël, Wim Van Gansbeke, and Peter Van Eenoo. 2012. “Development of a Sensitive GC-C-IRMS Method for the Analysis of Androgens in Doping Control.” In Benelux Association of Stable Isotope Scientists, Annual Meeting, Abstracts, 21–21. Arnhem, Nederland: Cito Arnhem.
Chicago author-date (all authors)
Polet, Michaël, Wim Van Gansbeke, and Peter Van Eenoo. 2012. “Development of a Sensitive GC-C-IRMS Method for the Analysis of Androgens in Doping Control.” In Benelux Association of Stable Isotope Scientists, Annual Meeting, Abstracts, 21–21. Arnhem, Nederland: Cito Arnhem.
Vancouver
1.
Polet M, Van Gansbeke W, Van Eenoo P. Development of a sensitive GC-C-IRMS method for the analysis of androgens in doping control. In: Benelux Association of Stable Isotope Scientists, Annual meeting, Abstracts. Arnhem, Nederland: Cito Arnhem; 2012. p. 21–21.
IEEE
[1]
M. Polet, W. Van Gansbeke, and P. Van Eenoo, “Development of a sensitive GC-C-IRMS method for the analysis of androgens in doping control,” in Benelux Association of Stable Isotope Scientists, Annual meeting, Abstracts, Nijmegen, The Netherlands, 2012, pp. 21–21.
@inproceedings{3010271,
  abstract     = {{All doping control laboratories accredited by the World Anti-Doping Agency (WADA) have been confronted with the task to develop analytical methods and establish criteria that allow endogenous steroids to be distinguished from their synthetic copies. It has been known for some time that gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is capable of meeting this challenge by comparison of the 13C/12C ratios of the target compounds with those of endogenous reference compounds that are not affected by the administration of synthetic androgens. Testosterone and/or its main metabolites function as target compounds. Typical endogenous reference compounds include 5β-pregnanediol, 11-ketoetiocholanolone and 11-βhydroxyandrosterone. Synthetic copies are generally derived from stigmasterol and sitosterol; plant sterols obtained from soybean (Glycine max) which have a significantly different carbon isotope composition compared to endogenous steroids. As a consequence, the administration of synthetic analogs is detectable through a change in the carbon isotopic composition of testosterone and its metabolites.
GC-C-IRMS however remains a very laborious and expensive technique because one can only determine the 13C/12C ratio of a pure compound. This means that a lot of purification steps have to be conducted and fractionation caused by one of these steps is unacceptable. On top of that, substantial amounts of urine are needed to meet the sensitivity requirements of the IRMS. Because the amount of received urine from an athlete is limited, doping control laboratories have to make their analysis as sensitive as possible so all the required doping tests can be executed. If less urine is consumed, then there is more available for additional tests. In this work we introduce a new type of injection which takes GC-C-IRMS to the next level. With the aid of a programmed temperature vaporizer we were able to increase the sensitivity of the IRMS with a factor of 10 and we drastically reduced the required amount of urine and the limit of detection. All this is achieved without having to change any of the IRMS detection parameters.}},
  author       = {{Polet, Michaël and Van Gansbeke, Wim and Van Eenoo, Peter}},
  booktitle    = {{Benelux Association of Stable Isotope Scientists, Annual meeting, Abstracts}},
  keywords     = {{androgens,doping control,solvent vent injection,GC-C-IRMS}},
  language     = {{eng}},
  location     = {{Nijmegen, The Netherlands}},
  pages        = {{21--21}},
  publisher    = {{Cito Arnhem}},
  title        = {{Development of a sensitive GC-C-IRMS method for the analysis of androgens in doping control}},
  year         = {{2012}},
}