Session: Advances in Mass Spectrometry:

Glucocorticoids have been prohibited by the World Anti-Doping Agency (WADA) due to their ability to increase athlete performance by inhibiting the response of inflammatory genes. Conventional methods of analysis have utilized gas chromatography (GC) or liquid chromatography (LC) coupled to mass spectrometry (i.e., GC- or LC-MS), but these targeted methods can be challenged with definitive identification of novel compounds with similar structure. The addition of ion mobility spectrometry (IMS), a structure-based gas-phase separation technique, can potentially provide more information about minor structural and stereochemical differences. Furthermore, measurement of an ion’s characteristic collision cross section (CCS) can be used to improve confidence of identification for targeted analytes in complex biological matrixes such as urine. We have previously measured CCS for several glucocorticoids including cortisone (214.5 Å²) and demonstrated the ability to resolve stereoisomers such as betamethasone (215.6 Å²) and dexamethasone (217.5 Å²). Studies are underway to characterize the remaining WADA prohibited glucocorticoids. This CCS information, coupled with chromatographic retention time, high resolution accurate mass, and MS/MS fragmentation pattern will allow for comprehensive identification and quantification of glucocorticoids using the developed LC-IM-MS/MS method. Finally, these substances will be spiked into pooled human urine, extracted using an established solid-phase extraction (SPE) preparation protocol, and analyzed at relevant concentrations to determine sensitivity and limits of detection.

Shon Neal

Appearances