Blackledge Robert D
Clin Chim Acta. 2009 Aug;406(1-2):8-13. doi: 10.1016/j.cca.2009.05.016. Epub 2009 May 22.
In 2006 Floyd Landis won the world's most prestigious bicycle race, the Tour de France. However, not many days after the race's conclusion it was released to the press that the Laboratoire National de Dépistage du Dopage (LNDD) had found Landis' urine after stage 17 positive for synthetic testosterone.
This review examines the instrumental data and methodology used by LNDD in the Landis case. The conclusions reached by LNDD were based on results of 2 separate instrumental methods. Subsequent to urine extraction and possibly derivatization, samples were initially screened via gas chromatography/mass spectrometry (GC/MS) using selected ion monitoring (SIM) to measure the ratio of testosterone to epitestosterone (T/E). Final confirmation of exogenous testosterone was determined by measuring the (13)C/(12)C stable isotope ratios in 4 metabolites of testosterone via gas chromatography combustion stable isotope ratio mass spectrometry (GC-C-IRMS).
T/E ratios determined by LNDD in Landis' stage 17 urine were unreliable due to the combined factors of an unsatisfactory extraction, high GC background, failure to obtain baseline peak separation for epitestosterone, unreliable quantization of the epitestosterone peak due to both peak overlap and because it was barely above background noise, and because only a single ion mass (432) rather than a minimum of 3 was used for SIM (in violation of both LNDD's SOP and WADA procedures). GC-C-IRMS methodology is less well known to the analytical chemistry community, but here too the results obtained by LNDD were unreliable. GC-C-IRMS errors can be briefly summarized as uncertain peak identification, unsuitable standards, and unreliable (and possibly biased) calculation of (13)C/(12)C ratios due to peak overlap as well as LNDD's usage of manual peak integration rather than use of the instrument system software.
2006年，弗洛伊德·兰迪斯赢得了世界最负盛名的自行车赛——环法自行车赛。然而，在比赛结束后不久，媒体就报道称，法国国家反兴奋剂检测实验室（LNDD）发现兰迪斯在第17赛段后的尿液中合成睾酮呈阳性。
本综述考察了LNDD在兰迪斯一案中所使用的仪器数据和方法。LNDD得出的结论基于两种独立仪器方法的结果。在尿液提取并可能进行衍生化处理之后，样本首先通过气相色谱/质谱联用仪（GC/MS），采用选择离子监测（SIM）技术来测量睾酮与表睾酮的比例（T/E）。通过气相色谱燃烧稳定同位素比率质谱仪（GC-C-IRMS）测量睾酮的4种代谢物中的（13）C/（12）C稳定同位素比率，从而对外源性睾酮进行最终确认。
由于提取不充分、气相色谱背景过高、表睾酮未能实现基线峰分离、表睾酮峰因峰重叠且几乎仅略高于背景噪声而导致定量不可靠，以及在SIM中仅使用了单个离子质量（432）而非至少3个（违反了LNDD的标准操作规程和世界反兴奋剂机构的程序）等综合因素，LNDD测定的兰迪斯第17赛段尿液中的T/E比率并不可靠。气相色谱燃烧稳定同位素比率质谱仪方法对于分析化学界来说不太为人所知，但LNDD在此处获得的结果同样不可靠。气相色谱燃烧稳定同位素比率质谱仪的误差可简要概括为峰识别不确定、标准不合适，以及由于峰重叠导致（13）C/（12）C比率的计算不可靠（且可能存在偏差），还有LNDD使用手动峰积分而非仪器系统软件。
