title: Characterization of the designer drug deschloroketamine (2-methylamino-2-phenylcyclohexanone) by gas chromatography/mass spectrometry, liquid chromatography/high-resolution mass spectrometry, multistage mass spectrometry, and nuclear magnetic resonance.
abstract: BACKGROUND
  Clinical and forensic toxicology laboratories are challenged every day by the analytical aspects of the new psychoactive substances phenomenon. In this study we describe the analytical characterization of a new ketamine derivative, deschloroketamine (2-methylamino-2-phenylcyclohexanone), contained in seized powders.
  
  
  METHODS
  The analytical techniques employed include gas chromatography/mass spectrometry (GC/MS), liquid chromatography/electrospray ionization coupled with Orbitrap high-resolution/MS (LC/ESI-HRMS), multistage MS (ESI-MS(n)), and NMR. The LC/ESI-HRMS analyses consisted of accurate mass measurements of MH(+) ions in full-scan mode; comparison of experimental and calculated MH(+) isotopic patterns; and examination of the isotopic fine structure (IFS) of the M + 1, M + 2, M + 3 isotopic peaks relative to the monoisotopic M + 0 peak. The collision-induced product ions of the MH(+) ions were studied by both HRMS and MS(n). (1)H and (13)C NMR measurements were carried out to confirm the chemical structure of the analyte.
  
  
  RESULTS
  The EI mass spectra obtained by GC/MS analysis showed the presence of molecular ions at m/z 203, and main fragment ions at m/z 175, 174, 160, 147, 146, and 132. The application of LC/ESI-HRMS allowed us to obtain: the accurate mass of deschloroketamine MH(+) ions with a mass accuracy of 1.47 ppm; fully superimposable experimental and calculated MH(+) isotopic patterns, with a relative isotopic abundance value of 3.69 %; and the IFS of the M + 1, M + 2, M + 3 isotopic peaks completely in accordance with theoretical values. Examination of the product ions of MH(+), as well as the study of both (1)H and (13)C NMR spectra, enabled the full characterization of the molecular structure of deschloroketamine.
  
  
  CONCLUSIONS
  The combination of the employed analytical techniques allowed the characterization of the seized psychoactive substance, in spite of the lack of a reference standard. Deschloroketamine is a ketamine analogue considered to be more potent and longer lasting than ketamine, and this paper is probably the first to report on its analytical characterization.
authors.affiliation: Laboratory of Environmental Hygiene and Forensic Toxicology, Department of Prevention, Azienda ULSS 12, Veneziana, Italy.
authors.forename: Giampietro
authors.initials: G
authors.lastname: Frison
authors.affiliation: Laboratory of Environmental Hygiene and Forensic Toxicology, Department of Prevention, Azienda ULSS 12, Veneziana, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Zamengo
authors.affiliation: Laboratory of Environmental Hygiene and Forensic Toxicology, Department of Prevention, Azienda ULSS 12, Veneziana, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Zancanaro
authors.affiliation: IENI - CNR, Corso Stati Uniti 4, 35127, Padova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Tisato
authors.affiliation: IENI - CNR, Corso Stati Uniti 4, 35127, Padova, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Traldi
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D015198:Designer Drugs / Q000032:analysis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007649:Ketamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D015198:Designer Drugs; D007649:Ketamine