Study on electron ionization-mass spectrometry characteristic fragments and cleavage patterns of fentanyl-type new psychoactive substances

Fentanyl-type new psychoactive substances (fentanyl-type NPS) are the primary subclass of synthetic opioid groups in new psychoactive substances (NPS). According to World Drug Report 2022 by the United Nations Office on Drugs and Crime, fentanyl-type NPS are the major cause of overdose deaths in North America, where their abuse is the most severe. Given the multiple modification sites in the structures of fentanyl-type NPS, the derivatization rate is very rapid, causing more difficulties for analysis and identification in forensic laboratories. Because the fragments in electron ionization-mass spectrometry (EI-MS) spectra contain rich structural infor-mation and similar compounds have similar MS cleavage patterns and produce similar characteristic fragments, it is crucial to infer the structure of emerging fentanyl-type NPS by summarizing the cleavage patterns and distinct fragments of fentanyl-type NPS EI-MS data. In this study, 49 fentanyl-type NPS were analyzed using gas chromatography-MS (GC-MS) with EI and chemical ionization sources. Subsequently, the EI-MS cleavage rules and characteristic fragments of fentanyl-type NPS were summarized with the assistance of 129 fentanyl-type NPS GC-MS data obtained from www.caymanchem.com. Furthermore, a set of structural analysis procedures was established to determine the structures of emerging fentanyl-type NPS. This procedure laid the foundation for rapid identification and screening of fentanyl-type NPS.