Pittcon 2018
FAIMS-MS Strategies for Separating Drug Isomers
205B
850-7
10:25am - 10:45am
Tue, Feb 27
Wei, Michael - University of Florida
Co-authors: Kemperman, Robin H - University of Florida, Yost, Richard A - University of Florida
High-field asymmetric-waveform ion mobility spectrometry (FAIMS) is an emerging technology that has great potential for targeted applications. FAIMS utilizes an alternating asymmetric electric field to separate ions by their different mobilities at high- and low-fields as they travel through the separation space. When coupled to mass spectrometry, FAIMS enhances the separation of analytes from other interfering compounds with little to no increase in analysis time. Several strategies have been investigated to improve the FAIMS separation for small isomeric molecules. These strategies include adding solvent vapor to the FAIMS cell and using various cations to form ion complexes that enhance ion mobility differences between isomers.
In this work, we utilize these strategies to separate isomers for two groups of drugs: anabolic androgenic steroids and opioids. The use of anabolic steroids as performance enhancing substances is prohibited in sporting events by the World Anti-Doping Agency, leading some athletes to use designer steroids to evade detection. Opioid addiction is an escalating problem that is compounded by the introduction of synthetic opiate analogues such as fentanyl. Screening methods for both of these compound classes are being challenged by the availability of synthetically manufactured analogues, including isomers of existing substances.
Solvent vapor addition has been demonstrated to dramatically improve analyte separation in FAIMS-MS. When dry nitrogen gas is used in the FAIMS cell, the FAIMS peaks for the [M+H]+ ions of morphine and norcodeine cannot be resolved (m/z 286). However, when a mixture of nitrogen gas and acetonitrile vapor is used, morphine is baseline resolved from norcodeine. Cation addition can produce ion adducts for specific isomers that result in unique FAIMS peaks. For example, the [2M+K]+ ion for testosterone (m/z 615) results in two peaks, with one peak that is fully separated from the single peak of epitestosterone.
