TECHNICAL NOTE CRIMINALISTICS
Stereochemical Analysis of Methorphan Using (−)-Menthyl Chloroformate
Article first published online: 7 MAY 2012
© 2012 American Academy of Forensic Sciences
Journal of Forensic Sciences
Volume 57, Issue 6, pages 1549–1555, November 2012
How to Cite
Koo, C., Cox, M., Klass, G. and Johnston, M. (2012), Stereochemical Analysis of Methorphan Using (−)-Menthyl Chloroformate. Journal of Forensic Sciences, 57: 1549–1555. doi: 10.1111/j.1556-4029.2012.02162.x
- Issue published online: 29 OCT 2012
- Article first published online: 7 MAY 2012
- Received 20 May 2011; and in revised form 19 Aug. 2011; accepted 11 Sept. 2011.
- forensic science;
- forensic chemistry;
- stereochemical analysis;
- gas chromatography–mass spectrometry
Abstract: 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.