Stereochemical Analysis of Methorphan Using (-)-Menthyl Chloroformate

Christina Koo, Matthew Cox, Gunter Klass, Martin Johnston

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)


    Forensic laboratories around the world have seen an increase in the number of drug seizures containing methorphan. Levomethorphan is a narcotic and a controlled substance, and its enantiomer dextromethorphan is an antitussive agent used in over-the-counter medications. For the forensic analysis of seized drugs containing methorphan, it is important to report the stereochemical composition of the drug. Ideally, a method based on common forensic laboratory instrumentation is desirable. The use of the chiral derivatizing agent (-)-menthyl chloroformate followed by routine gas chromatography-mass spectrometry analysis of the derivative was shown to successfully determine the stereochemical composition of methorphan. This approach was applied to a street seizure containing methorphan proving that it was pure dextromethorphan. The derivatives of dextro- and levomethorphan were subjected to mass spectroscopic and nuclear magnetic resonance analysis, which confirmed that the structure of the derivatives remained unchanged as a result of the derivatization process.

    Original languageEnglish
    Pages (from-to)1549-1555
    Number of pages7
    JournalJournal of Forensic Sciences
    Issue number6
    Publication statusPublished - Nov 2012


    • Dextromethorphan
    • Forensic chemistry
    • Forensic science
    • Gas chromatography-mass spectrometry
    • Levomethorphan
    • Stereochemical analysis


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