Identification of substituted cathinones: 3,4-Methylenedioxy derivatives by high performance liquid chromatography-quadrupole time of flight mass spectrometry.

The potential of high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) for screening of synthetic cathinones in legal highs was examined. Samples were analysed by liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometer (Q/TOF). Nanoelectrospray ionisation (nanoESI) was employed. MS and MS/MS spectra were acquired. Six 3,4-methylenedioxy derivatives: methylone, butylone, pentylone, MDPBP, MDPV and BMDP were detected and identified. The fragmentation pattern of 3,4-methylenedioxy derivatives in collision induced dissociation (CID) was derived and described, which will facilitate future screenings and identifications of new synthetic cathinones. For 3,4-methylenodioxy derivative cathinones the loss of neutral groups CH₄O₂, H₂O, amines and imines is observed. The loss of water and the methylenedioxy group does not occur when cyclic amino group - pyrrolidynyl is present in the molecule. Phenyloxazole cations are formed when CH₄O₂ is lost. The formation of the metylenedioxybenzoyloxonium and allyldioxybenzoyloxonium ions is typical for 3,4-methylenodioxy derivatives, however, the formation of the former appears to be inhibited by the presence in the molecule of the group of atoms able to form very stable tropylium carbocation.