Sensitive detection and primary metabolism analysis of flualprazolam in blood.

Flualprazolam, a new benzodiazepine psychoactive substance recently made available online, and outside the controlled substance list, is often used by criminals for rape and robbery. In this paper, flualprazolam was successfully identified by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) and nuclear magnetic resonance (NMR). Moreover, LC-Q-TOF-MS analysis method was proposed for the determination of flualprazolam in whole blood using the rabbit perfusion model. After metabolism analysis, a monohydroxylated metabolite 3-hydroxy-flualprazolam was found in the primary mass spectrum of metabolites. Meanwhile, the time effect curve of the flualprazolam in rabbit's blood was explored and the detection window was about 36 h. Moreover, the sensitivity of the established LC-Q-TOF-MS method was investigated with the limit of detection of 0.03 ng/mL. The successful analysis of an actual forensic case with this established method suggests that it might provide a reference method for drug detection or supervision in law enforcement agencies and identification institutions.