Mass Fragmentation Characteristics of Piperazine Analogues

Piperazine analogues are one of the most important types of new psychoactive substances (NPS) drugs. They have been found to produce amphetamine-like effects which can cause toxic effects including agitation, anxiety and cardiac symptoms. The fragmentation mechanism of piperazine analogues is of great importance to realize the rapid detection of target objects in actual drug crime. According to the connection mode of piperazine ring and benzene ring in the backbone structure, piperazine analogues can be divided into benzylpiperazines and phenylpiperazines. However, there was no research on the fragmentation pathways of piperazine analogues by now. In order to obtain accurate and comprehensive information of the fragmentation pathways of piperazines, benzylpiperazine (BZP), 1,4-dibenzylpiperazine (DBZP), 1-(3-chlorophenyl)-piperazine (mCPP) and 1-(3-trifluoromethylphenyl)-piperazine (TFMPP) were selected and analyzed by electrospray ionization tandem mass spectrometry (ESI-MS) at collision induced dissociation (CID) mode. The analysis was performed on SHISEIDO CAPCELL PAK C18 MG column（150 mm×3 mm×3 μm） with 0.1% formic aqueous solution (A)-acetonitrile (B) as gradient elution by triplequadrupole tandem mass spectrometry (QQQ-MS/MS). The CID fragmentation routes were speculated. Four piperazine compounds showed good responses at positive ion detection mode as M+H⁺ ions in MS spectrum. MS2 spectra showed that the C—N bonds between the piperazine ring and the benzene ring and the C—N bonds within the piperazine ring were easily cleaved into characteristic ions. The high-abundance characteristic ions for benzylpiperazines (BZP and DBZP) was m/z 91, common fragment ions for phenylpiperazines were m/z 119, m/z 70 and m/z 56, the typical fragment ions for mCPP were m/z 154, m/z 140 and the typical fragment ions for TFMPP were m/z 188, m/z 174. The investigation of fragmentation pathways of 4 piperazine analogues can provide important references for rapidly structural identification of piperazine type new psychoactive substances.