New impurity profiles of recent Australian imported ‘ice’: Methamphetamine impurity profiling and the identification of (pseudo)ephedrine and Leuckart specific marker compounds

Determination of the synthetic route in methamphetamine profiling relies on the identification of key, route specific marker impurity compounds. Impurity profiling of recent crystalline methamphetamine (‘ice’), seized by the Australian Federal Police at the Australian border in 2003–2004, identified route specific marker compounds normally associated with two different synthetic approaches in the same samples. Impurities consistent with the ephedrine route included 1,2-dimethyl-3-phenyl aziridine (I), 1,3-dimethyl-2-phenylnaphthalene (VIII) and 1-benzyl-3-methylnaphthalene (IX), alongside N-formylmethamphetamine (V), N,N-di-(β-phenylisopropyl)amine (XII) and N,N-di-(β-phenylisopropyl)methylamine (XIII), N-benzoylamphetamine (XIV) and N,N-di-(β-phenylisopropyl)formamide (XV) commonly associated with the Leuckart route and/or reductive amination. A non-synthetic process related origin of low-level N-formylmethamphetamine is proposed.