[Determination of 4-bromo-2,5-dimethoxyamphetamine (DOB) found in illicit tablets seized in Italy]

Some of the molecules belonging to the amphetamines group (4-bromo-2,5-dimethoxyamphetamine, DOB) or to the phenethylamines (4-bromo-2,5-dimethoxy-phenethylamine, 2C-B or Nexus) have closely related structures that make their identification quite difficult. The unambiguous identification is crucial in forensic responses. This paper describes the analytical approach used to achieve the identification of the main ingredient contained in tablets seized in the illicit market of Rome (Italy) and submitted to our laboratory by the Court of Law of Rome. The procedure entails the basic extraction of the main ingredient from the tablets with tert-butyl methyl ether followed by qualitative gas chromatographic mass-spectrometric (GC-MS) analysis using both electron impact detection (EI) and chemical ionization (CI). The examination of the mass spectra obtained from the native molecule and from its pentafluoropropionyl-derivative allows the structural identification of the side chain and the substitutions on the aromatic ring. This analytical approach can thus be useful to distinguish between amphetamine-like and phenetylamine-like compounds using instruments and techniques commonly available in the forensic toxicology laboratories.