To explore the fragmentation patterns of etomidate analogues by mass spectrometry to provide reference for the identification and structural analysis of these substances.
Etomidate, metomidate, propaxate and isopropaxate were analyzed by gas chromatography-quadrupole time-of-flight mass spectrometry(GC-Q TOF MS) and liquid chromatography high-resolution mass spectrometry (LC-Q Orbitrap MS) under EI and ESI positive ionization modes. And the EI-MS and ESI-MS/MS fragmentation patterns of etomidate analogues were deduced.
Etomidate and its analogues had similar fragmentation pathways. In EI-MS mode, the fragmentation pathway was mainly focused on the breaking of carbon-nitrogen bonds, and the specific fragment ions (m/z 105 and m/z 77) were formed. In ESI-MS/MS positive ion mode, the fragmentation pathway was mainly focused on the fracture of carbon-nitrogen bond, resulting in the formation of the characteristic fragment ion with styrene as neutral loss, Subsequently, the neutral fragments R1 and H2O were lost in turn, and the specific fragment ions (m/z 113 and m/z 95) was formed. Moreover, the neutral loss of R1 in ESI-MS/MS positive ion mode could more intuitively indicate the substituents on the parent nucleus and further determine the structure of etomidate and its analogues.
The fragmentation patterns of etomidate and its analogues are helpful to analyze and infer the structure of these substances, and provide reference for the identification and structural analysis of these substances in forensic laboratory.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |