Improved Identification of Isomeric Steroids Using the Paternò-Büchi Reaction with Ion Mobility-Mass Spectrometry.
Samuel W MaddoxStine S H OlsenDiana C VelosaAurora Burkus-MatesevacRoberto PeveratiChristopher D ChouinardPublished in: Journal of the American Society for Mass Spectrometry (2020)
The Paternò-Büchi (PB) reaction is a common organic reaction in which a carbonyl radical formed by exposure to UV radiation reacts with an alkene to form an oxetane ring. Recent analytical applications of this reaction have included the determination of C═C bond position in lipid fatty acyl tails using tandem mass spectrometry. Our group has recently investigated methods for structurally modifying steroid isomers to improve their identification and resolution using ion mobility spectrometry. Herein, we report the first application of the Paternò-Büchi reaction to form steroid oxetanes using a simple, low-cost, and high efficiency method with a low pressure mercury lamp. This methodology is performed on several endogenous steroid isomers, resulting in unique ion mobility spectra that provide a unique fingerprint for each. These fingerprint spectra can add confidence in identification of those compounds, especially in complex biological matrixes. Testosterone and epitestosterone, an epimer pair commonly interrogated in a number of applications such as for their use as performance enhancing drugs, displayed one and three unique ion mobility peaks, respectively. These spectra and their measured collision cross sections (CCS) allow for unambiguous differentiation of these and several other steroid isomer groups analyzed in this work. Finally, multiple anabolic androgenic steroids prohibited by the World Anti-Doping Agency were tested with this method and resulted in unique CCS for their PB reaction products. This approach can offer improved confidence in their identification as well as for many other banned substances.
Keyphrases
- liquid chromatography
- tandem mass spectrometry
- mass spectrometry
- low cost
- gas chromatography
- high performance liquid chromatography
- high efficiency
- solid phase extraction
- electron transfer
- bioinformatics analysis
- ultra high performance liquid chromatography
- single molecule
- ms ms
- high resolution mass spectrometry
- replacement therapy
- drug induced