Improved analysis of derivatized steroid hormone isomers using ion mobility-mass spectrometry (IM-MS)

Separation and Characterization of Synthetic Cannabinoid Metabolite Isomers Using SLIM High-Resolution Ion Mobility-Tandem Mass Spectrometry (HRIM-MS/MS)

Synthetic cannabinoids, a subclass of new psychoactive substances (NPS), are laboratory-made substances that are chemically similar to those found naturally in the cannabis plant. Many of these substances are illicitly manufactured and have been associated with severe health problems, prompting a need to develop analytical methods capable of characterizing both known and previously undetected compounds. This work focuses on a novel Structures for Lossless Ion Manipulations (SLIM) IM-MS approach to the differentiation and structural characterization of synthetic cannabinoid metabolites, specifically MDA-19/BUTINACA, JWH-018, and JWH-250 isomer groups. These different compound classes are structurally very similar, differing only in the position of one or a few functional groups; this yielded similarity in measured collision cross section (CCS) values. However, the high resolution of SLIM IM provided adequate separation of many of these isomers, such as sodiated JWH-250 metabolites N-4-OH, N-5-OH, and 5-OH, which displayed CCS of 187.5, 182.5, and 202.3 Å2, respectively. In challenging cases where baseline separation was precluded due to nearly identical CCS, such as for JWH-018 isomers, simple derivatization by dansyl chloride selectively reacted with the 6-OH compound to provide differentiation of all isomers using a combination of CCS and m/z. Finally, the opportunity to use this method for structural elucidation of unknowns was demonstrated by using SLIM IM mobility-aligned MS/MS fragmentation. Different MDA-19/BUTINACA isomers were first mobility separated and could then be individually activated, yielding unique fragments for both targeted identification and structural determination. Overall, the described SLIM IM-MS/MS workflow provides significant potential as a rapid screening tool for the characterization of emerging NPS such as synthetic cannabinoids and their metabolites.

Implementation of charged microdroplet-based derivatization of bile acids on a cyclic ion mobility spectrometry-mass spectrometry platform

Herein, we report the first implementation of charged microdroplet-based derivatization on a commercially-available cyclic ion mobility spectrometry-mass spectrometry platform. We have demonstrated the potential of our approach to improve separability of challenging isomers, but more importantly to rapidly screen derivatization reactions through droplet chemistry. Additionally, the use of cyclic ion mobility separations and tandem mass spectrometry reveals insights into product formation that would be lost with single stage mass spectrometry. Overall, we anticipate broad utility of our methodology owing to the simple design and setup for performing these droplet-based reactions and future work coupling these reactions online with liquid chromatography.