Abstract des Autors

In 2013, the World Anti-Doping Agency (WADA) drastically lowered the minimum required performance levels (MRPLs) of most doping substances, demanding a substantial increase in sensitivity of the existing methods that were employed in doping control laboratories around the world. For a number of compounds, conventional electron impact ionization gas chromatography tandem mass spectrometry (GC-El-MS/MS) is often no longer sufficient to reach these MRPLs and new strategies are required. Both quantitative and qualitative compounds need to be included in the screening method and both require a different focus and approach. In this study, the capabilities of positive chemical ionization (PCI) GC-MS/MS are investigated for a wide range of drug related compounds of various classes and chemical families. An increased sensitivity is obtained for 113 out of 120 compounds by using PCI with ammonia as reagent gas compared to GC-EI-MS/MS. Due to the occurrence of more selective transitions, the sensitivity increases on average with a factor of 50 with a maximum sensitivity increase of a factor 1000. A new GC-PCI-MS/MS method has been developed and validated for the detection of a wide variety of exogenous doping substances and the quantification of 16 endogenous steroids in urine in compliance with the required MRPLs established by WADA in 2013. The increased sensitivity allows the set up of a balanced screening method that meets the requirements for both quantitative and qualitative compounds: sufficient capacity and resolution and a high sensitivity with a short analysis time.