ABSTRACT The nonmedical use of etomidate and its structural analogs as additives in e‐cigarettes has shown a significant growth trend, and the public health and safety risks arising from the abuse of such substances have drawn widespread attention. This study comprehensively employed gas chromatography–mass spectrometry, liquid chromatography–high‐resolution mass spectrometry, and nuclear magnetic resonance spectroscopy (NMR) techniques to identify a novel metomidate analog, 4‐fluorometomidate, in seized cartridges for the first time. Mass spectrometry analysis revealed that under electron ionization conditions, the compound produced fragment ions at m/z 77.1, 95.1, 103.1, 123.1, and 248.1. The molecular ion ( m/z 248.1) and base peak ( m/z 123.1) were both 18 Da higher than the corresponding peaks ( m/z 230.1 and 105.1) characteristic for metomidate. In electrospray ionization mode, its protonated molecule ( m/z 249.1032) also exhibited an increase of 17.9908 Da compared to metomidate ( m/z 231.1124), and the characteristic fragment at m/z 123.0607 showed an increase of 17.9909 Da relative to the fragment of metomidate ( m/z 105.0698), which was overall consistent with the substitution of one hydrogen atom by a fluorine atom (△ m/z 17.9905). NMR analysis confirmed that the fluorine atom is located at the 4′‐position of the benzene ring.
Feng et al. (Sun,) studied this question.