The analysis of amphetamine-like cathinone derivatives using positive electrospray ionization with in-source collision-induced dissociation.

Amphetamine-like cathinone derivatives have become popular as recreational drugs over the past several years but their identification for forensic purposes is made difficult as they undergo extensive fragmentation under commonly used electron ionization (EI) conditions to afford ambiguous mass spectra. To overcome this, the feasibility of using positive electrospray ionization (ESI) with in-source collision-induced dissociation (CID) to produce distinguishable product ion mass spectra was examined. A set of six homologous cathinone derivatives was analyzed using an LTQ/Orbitrap™ high-resolution mass spectrometer to establish if there are any commonalities or uniqueness in their mass spectra. These compounds and a number of other cathinone derivatives were also analyzed on a single quadrupole mass spectrometer to establish the feasibility of using in-source CID for their identification in forensic drug samples. The ESI product ion mass spectra of the [M + H](+) ions of six model compounds were found to be readily interpretable and product ion formation pathways are presented. The use of such mass spectral data in the analysis of forensic drug samples facilitated the discrimination of closely related cathinone derivatives that were difficult to distinguish using conventional gas chromatography/electron ionization mass spectrometry. A product ion mass spectral library of 22 commonly encountered cathinone derivatives was also developed. It has been shown that the product ion ESI mass spectra of cathinone derivatives are readily interpretable and are useful for the identification of this drug group in forensic samples.