Direct-infusion electrospray ionization-mass spectrometry profiling of fentanyl and acetylfentanyl reaction mixtures

The widespread distribution and variety of fentanyl-related opioids has prompted many forensic researchers to begin exploring new techniques to carefully process and identify the many components of these seized exhibits. While these analyses typically consist of chromatographic separation, this can be a tedious and time-consuming process. To improve upon the accurate detection and structural elucidation of the components of these complex samples, a direct-infusion technique was utilized with ESI–MS on both a triple quadrupole and Orbitrap mass spectrometer to both structurally identify and propose reaction mechanisms for minor, unknown components. Results from these direct-infusion experiments suggest amine oxide formation and O-acetylation within crude reaction mixtures of both fentanyl and acetylfentanyl producing ions at m/z 395 and 353, respectively. Other previously detected components, including both byproducts and degradation products, of these samples have also been identified by their exact masses and fragmentation. Complementary fragmentation and exact mass data from these experiments can be used to accurately profile new, unknown components and help exclude potential isobaric interferences.