Determination of Origin of Ephedrine Used as Precursor for Illicit Methamphetamine by Carbon and Nitrogen Stable Isotope Ratio Analysis

Abstract

The sale of ephedrine, one of the precursors of methamphetamine, is strictly controlled and monitored in various countries to prevent the production of illicit methamphetamine. There are three kinds of production scheme for ephedrine manufacture, and it is very useful for precursor control to investigate the origin of ephedrine used for the synthesis of illicit methamphetamine. By means of stable isotope ratio mass spectrometry (IR-MS), we investigated the origin of ephedrine based on the delta(13)C and delta(15)N values. The various origins of ephedrine (biosynthetic, semisynthetic, or synthetic) could be discriminated clearly by using these values. The delta(15)N values of synthetic ephedrine were more negative than those of ephedrine from other sources. By the repeated distillation of methylamine in our laboratory, we confirmed that this could be due to isotope separation during distillation for the purification of methylamine used for ephedrine synthesis. The values for ephedrine used as the precursor were well-correlated with those for methamphetamine synthesized from it. This drug characterization analysis should be useful to illuminate the origin of the precursors used for clandestine methamphetamine and to trace the diversion of medicinal ephedrine for illicit manufacture of methamphetamine.

Forensic applications of isotope ratio mass spectrometry—A review

“…Kurashima et al [99] analysed a range of ephedrine samples from different origins, i.e. biosynthetic, semisynthetic and synthetic, using EA/IRMS.…”

Seized methamphetamine samples with unique profiles of stable nitrogen isotopic composition documented by stable isotope ratio mass spectrometry

“…The isotopic compositions of synthetic substances depend on isotopic variations in the starting materials and also isotopic fractionation during the synthetic processes. Kurashima et al [23] synthesized MA from six isotopically different ephedrines by the Nagai method. The δ 15 N difference between the starting material (ephedrine or pseudoephedrine) and the product (MA), which refl ected the isotopic fractionation during the synthetic process, was less than 0.6‰.…”

Recent Advances in the Application of Stable Isotope Ratio Analysis in Forensic Chemistry

“…Application of principal components analysis to the database indicated that 15N values and MDMA content were the two most important parameters of the database. Kurashima et al [12] investigated the possibility of determining geographic origin of ephedrine by carbon and nitrogen isotope abundances and analyzed ephedrine samples from three different synthetic routes. 13C values allowed the discrimination of semi-synthetic ephedrine from both synthetic and natural, but the latter two could not be separated.…”