δ¹³C,δ¹⁵N andδ²H isotope ratio mass spectrometry of ephedrine and pseudoephedrine: application to methylamphetamine profiling

Abstract

Conventional chemical profiling of methylamphetamine has been used for many years to determine the synthetic route employed and where possible to identify the precursor chemicals used. In this study stable isotope ratio analysis was investigated as a means of determining the origin of the methylamphetamine precursors, ephedrine and pseudoephedrine. Ephedrine and pseudoephedrine may be prepared industrially by several routes. Results are presented for the stable isotope ratios of carbon (delta(13)C), nitrogen (delta(15)N) and hydrogen (delta(2)H) measured in methylamphetamine samples synthesized from ephedrine and pseudoephedrine of known provenance. It is clear from the results that measurement of the delta(13)C, delta(15)N and delta(2)H stable isotope ratios by elemental analyzer/thermal conversion isotope ratio mass spectrometry (EA/TC-IRMS) in high-purity methylamphetamine samples will allow determination of the synthetic source of the ephedrine or pseudoephedrine precursor as being either of a natural, semi-synthetic, or fully synthetic origin.

Isotope fractionation during precipitation of methamphetamine HCl and discrimination of seized forensic samples

“…This means that any large differences in d 15 N and d 13 C between groups of samples should be due to the use of a different sample of precursor, and this has been indicated by results of previous studies [4,5,8]. In contrast, for d 2 H, changes in reaction conditions may lead to large changes in the observed isotope ratio.…”

“…Polarimetry results (Table 3) obtained for a selection of the samples indicated that it is highly likely the samples were synthesized from (À)-ephedrine and not phenyl-2-propanone. Consequently, IRMS results for this sample set can be discussed with reference to results from isotope studies on ephedrine and on methamphetamine synthesized from ephedrine [4][5][6]. Based on hierarchical cluster analysis (Fig.…”

“…This has resulted in increased clandestine synthesis and trafficking of the illicit drug [1]. Recent studies have increasingly focused on isotope analysis of methamphetamine and its precursors by isotope ratio mass spectrometry (IRMS) [2][3][4][5][6][7][8] and deuterium nuclear magnetic resonance spectroscopy ( 2 H NMR) [9,10]. It is thought that isotope analysis can provide sample linking information and intelligence information on the source of precursors, especially in cases where traditional forensic drug analysis techniques may fail.…”

Research Front Essay: Forensic Chemistry

“…[12] Readers may also find of interest a recent paper by Collins et al on IRMS of ephedrine and pseudoephedrine used to produce methamphetamine. [13] Finally, Niamh Nic Daeid and colleagues from the Centre for Forensic Science at the University of Strathdyde discuss the use of IRMS for forensic uses. [14] The reader is also referred to an earlier review by Benson et al [15] In conclusion, the forensic world provides almost untapped opportunities to apply chemistry in a practical and useful way.…”

Profiling of seized methamphetamine putatively synthesized by reductive amination of 1-phenyl-2-propanone

“…Recently, stable isotope ratio mass spectrometry (IRMS) has been increasingly used in analysis of MA and its precursors to obtain sample-linking information, especially in cases where conventional drug profiling may fail [7][8][9][10][11][12][13]. The isotopic compositions of synthetic substances depend on isotopic variations in the raw materials and isotopic fractionation during the synthetic process.…”