Session: Advances in Mass Spectrometry:

Advancements in analysis of compounds relevant to doping in sport are critically important. Emerging doping agents, including novel anabolic androgenic steroids (AAS), are constantly developed, and failure to establish reliable testing methods will result in the rampant use of illicit drugs without penalty. Ion mobility-mass spectrometry (IM-MS) provides high sensitivity, specificity, and analysis times on a millisecond timescale, as opposed to previous methods (i.e., chromatography) that take several minutes to hours. Ions are separated and characterized based on their gas-phase transport in an electric field. The differences in size, shape, and charge are collectively referred to as the rotationally averaged collision cross section (CCS). This is a key feature that we can take advantage of to successfully isolate and identify compounds of interest. Herein, IM-MS is used as a tool to characterize CCS for AAS listed on the World Anti-Doping-Agency (WADA) 2021 Prohibited List. Characterization was performed using an Agilent 6560 IM-QTOF, a drift tube-IMS (DTIMS) instrument that allows for direct measurement of CCS using the multi-step method. Furthermore, the single-field method was evaluated for its ability to accurately measure CCS on a chromatographic timescale. We have demonstrated that the error for these values, in comparison with their accepted multi-field values, is <1%. We evaluated several isomer groups, including testosterone, and epitestosterone which yielded CCS for their [M+H]⁺ ions of 173.9 ± 0.1 Å² and 174.2 ± 0.1 Å² respectively. CCS for their [M+Na]⁺ ions yielded 198.7 ± 0.1 Å² for testosterone, 199.6 ± 0.1 Å² for epitestosterone and 198.5 ± 0.1 Å²for prasterone. Isomer pairs aldosterone and cortisone, yielded CCS values of 187.6 ± 0.1 Å and 189.7 ± 0.1 for their [M+H]⁺ ions, and 199.4 ± 0.1 Å² and 215.23 ± 0.1 Å² for their [M+Na]⁺ ions respectively.

Christopher Chouinard

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