title: Identification and differentiation of methcathinone analogs by gas chromatography-mass spectrometry.
abstract: To overcome a number of challenges involved in analyzing methcathinone (MC) analogues, we performed gas chromatography-mass spectrometry (GC-MS) analysis, including sample preparation, of nine MC analogues - 4-methylmethcathinone, three positional isomers of fluoromethcathinones, 4-methoxymethcathinone, N-ethylcathinone, N,N-dimethylcathinone, buphedrone, and pentedrone. The MC analogues underwent dehydrogenation when the free bases were analyzed using splitless injection. Most of this thermal degradation was prevented using split injection. This indicated that a shorter residence time in the hot injector prevented decomposition. Uniquely, 2-fluoromethcathinone degraded to another product in a process that could not be prevented by the split injection. Replacing the liner with a new, clean one was also effective in preventing thermal degradation. Most of the analytes showed a substantial loss (>30%) when the free base solution in ethyl acetate was evaporated under a nitrogen stream. Adding a small amount of dimethylformamide as a solvent keeper had a noticeable effect, but it did not completely prevent the loss. Three positional isomers of fluoromethcathinones were separated with baseline resolution by heptafluorobutyrylation with a slow column heating rate (8 °C/min) using a non-polar DB-5 ms capillary column. These results will be useful for the forensic analysis of MC analogues in confiscated materials.
authors.affiliation: National Research Institute of Police Science, 6-3-1, Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan. tujikawa@nrips.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Tsujikawa
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Mikuma
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuwayama
authors.forename: Hajime
authors.initials: H
authors.lastname: Miyaguchi
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kanamori
authors.forename: Yuko T
authors.initials: YT
authors.lastname: Iwata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
mesh_terms: D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D054879:Halogenation; D007536:Isomerism; D011427:Propiophenones / Q000032:analysis*; D011619:Psychotropic Drugs / Q000032:analysis*; D013696:Temperature
chemical_list: D011427:Propiophenones; D011619:Psychotropic Drugs; C047806:monomethylpropion