Regioisomer Differentiation of Ring-Substituted Chloromethcathinones and Bromomethcathinones Using Gas Chromatography/Electron Ionization-Triple Quadrupole Energy-Resolved Mass Spectrometry

Takaya Murakami; Yuki Sakamoto; Natsuhiko Sugimura; Eriko Minami; Yoshiaki Iwamuro; Reiko Ishimaru; Satoshi Chinaka; Hiroshi Hasegawa

doi:10.1021/jasms.0c00358

Regioisomer Differentiation of Ring-Substituted Chloromethcathinones and Bromomethcathinones Using Gas Chromatography/Electron Ionization-Triple Quadrupole Energy-Resolved Mass Spectrometry

J Am Soc Mass Spectrom. 2021 Feb 3;32(2):601-605. doi: 10.1021/jasms.0c00358. Epub 2020 Dec 7.

Authors

Takaya Murakami^{1

2}, Yuki Sakamoto³, Natsuhiko Sugimura⁴, Eriko Minami¹, Yoshiaki Iwamuro¹, Reiko Ishimaru¹, Satoshi Chinaka^{1

5}, Hiroshi Hasegawa²

Affiliations

¹ Forensic Science Laboratory, Ishikawa Prefectural Police Headquarters, 1-1 Kuratsuki, Kanazawa 920-8553, Japan.
² Institute of Science and Engineering, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
³ Shimadzu Corporation, 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511, Japan.
⁴ Materials Characterization Central Laboratory, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan.
⁵ Department of Forensic Medicine and Pathology, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa 920-8640, Japan.

PMID: 33284010
DOI: 10.1021/jasms.0c00358

Abstract

Positional isomers o-, m-, and p-chloromethcathinones (CMCs) and m- and p-bromomethcathinones (BMCs) were effectively differentiated using gas chromatography (GC) and energy-resolved mass spectrometry (ERMS) analyses. GC demonstrated that the free bases of CMC and BMC isomers were simultaneously baseline-separated at a slow column heating rate (5 °C/min) using a conventional low-polar capillary column. ERMS showed that the trifluoroacetyl derivatives of the positional isomers differed in mass spectral abundances of both halophenyl and halobenzoyl cations. Moreover, the logarithmic plots of the abundance ratio of the two cations as a function of the collision energy (CE) exhibited marked differences among the isomers at each CE, following the order of ortho < para < meta for CMCs and para < meta for BMCs. The performed theoretical calculations of dissociation energy agreed well with the ERMS measurements. The GC and ERMS methodologies enabled unambiguous and reliable differentiation of CMC and BMC isomers. The developed approach is expected to significantly contribute to the accurate structural identification of new psychoactive substances in forensic, toxicological, and clinical fields.

Keywords: bromomethcathinone; chloromethcathinone; energy-resolved mass spectrometry; gas chromatography; new psychoactive substances; regioisomer differentiation.