ObjectiveTo identify metonitazene in e-liquids seized from drug cases.MethodsMethods of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) were established to identify metonitazene. The compound was also analyzed by ultraviolet-visible absorption spectrum (UV-Vis) , Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) methods.ResultsThe GC-MS result showed that there was an unknown compound at the retention time of 15.295 min, and its characteristic ions were m/z 86 (base peak) , 121, 58, and 382, which was identified as metonitazene by comparing with the standard substance. The structural information of the target acquired by UV-Vis, FTIR and NMR were supplemented.ConclusionThe comprehensive use of various techniques to analyze metonitazene in e-liquid samples can provide structural information to confirm the detection of this kind of new psychoactive substances.