Measurement of stable isotope ratios in methylamphetamine: A link to its precursor source

Salouros, H; Sutton, GJ; Howes, J; Hibbert, DB; Collins, M

Measurement of stable isotope ratios in methylamphetamine: A link to its precursor source

Salouros, H Sutton, GJ

Howes, J Hibbert, DB Collins, M

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Publication Type:: Journal Article
Citation:: Analytical Chemistry, 2013, 85 (19), pp. 9400 - 9408
Issue Date:: 2013-10-01

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Field	Value	Language
dc.contributor.author	Salouros, H	en_US
dc.contributor.author	Sutton, GJ https://orcid.org/0000-0003-3523-3499	en_US
dc.contributor.author	Howes, J	en_US
dc.contributor.author	Hibbert, DB	en_US
dc.contributor.author	Collins, M	en_US
dc.date.issued	2013-10-01	en_US
dc.identifier.citation	Analytical Chemistry, 2013, 85 (19), pp. 9400 - 9408	en_US
dc.identifier.issn	0003-2700	en_US
dc.identifier.uri	http://hdl.handle.net/10453/28164
dc.description.abstract	The illicit drug methylamphetamine is often prepared from the precursor ephedrine or pseudoephedrine, which in turn are obtained by three processes: extraction from the Ephedra plant ("natural"), via fermentation of sugars ("semi-synthetic"), and by a "fully synthetic" route from propiophenone. We report the first method to differentiate between the three industrial routes used to produce the precursors ephedrine and pseudoephedrine by measurement of stable isotope ratios of nitrogen (δ15N), hydrogen (δ2H), and carbon (δ13C). Analysis of 782 samples of seized methylamphetamine allowed classification into three groups using k-means clustering or the expectation-maximization algorithm applied to a Gaussian mixture model. By preparation of 30 samples of ephedrine by the "fully synthetic" industrial process and measuring their δ15N, δ2H, and δ13C values, we observed that 15N becomes significantly depleted compared to the methylamine starting material. Conversion of ten ephedrine samples to methylamphetamine showed that this depletion is maintained in the final drug product, of which the δ15N, δ13C, and δ2H values were distinct from those of ephedrine and methylamphetamine samples of a semi-synthetic (fermentation pathway) origin. Combining modeling analysis with the new experiments and published information on the values of δ2H gave a definitive assignment of the three model groups, and equations to obtain probabilities for the precursor origin of any new sample. A simple rule of thumb is also presented. Making an assignment using delta values is particularly useful when no other chemical profiling information is available. © 2013 American Chemical Society.	en_US
dc.relation.ispartof	Analytical Chemistry	en_US
dc.relation.isbasedon	10.1021/ac402316d	en_US
dc.subject.classification	Analytical Chemistry	en_US
dc.subject.mesh	Deuterium	en_US
dc.subject.mesh	Carbon Isotopes	en_US
dc.subject.mesh	Nitrogen Isotopes	en_US
dc.subject.mesh	Methamphetamine	en_US
dc.subject.mesh	Street Drugs	en_US
dc.subject.mesh	Molecular Structure	en_US
dc.subject.mesh	Chemistry, Pharmaceutical	en_US
dc.subject.mesh	Algorithms	en_US
dc.subject.mesh	Illicit Drugs	en_US
dc.title	Measurement of stable isotope ratios in methylamphetamine: A link to its precursor source	en_US
dc.type	Journal Article
utslib.citation.volume	19	en_US
utslib.citation.volume	85	en_US
utslib.for	0301 Analytical Chemistry	en_US
utslib.for	0399 Other Chemical Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Electrical and Data Engineering
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	closed_access
pubs.issue	19	en_US
pubs.publication-status	Published	en_US
pubs.volume	85	en_US

Abstract:

The illicit drug methylamphetamine is often prepared from the precursor ephedrine or pseudoephedrine, which in turn are obtained by three processes: extraction from the Ephedra plant ("natural"), via fermentation of sugars ("semi-synthetic"), and by a "fully synthetic" route from propiophenone. We report the first method to differentiate between the three industrial routes used to produce the precursors ephedrine and pseudoephedrine by measurement of stable isotope ratios of nitrogen (δ15N), hydrogen (δ2H), and carbon (δ13C). Analysis of 782 samples of seized methylamphetamine allowed classification into three groups using k-means clustering or the expectation-maximization algorithm applied to a Gaussian mixture model. By preparation of 30 samples of ephedrine by the "fully synthetic" industrial process and measuring their δ15N, δ2H, and δ13C values, we observed that 15N becomes significantly depleted compared to the methylamine starting material. Conversion of ten ephedrine samples to methylamphetamine showed that this depletion is maintained in the final drug product, of which the δ15N, δ13C, and δ2H values were distinct from those of ephedrine and methylamphetamine samples of a semi-synthetic (fermentation pathway) origin. Combining modeling analysis with the new experiments and published information on the values of δ2H gave a definitive assignment of the three model groups, and equations to obtain probabilities for the precursor origin of any new sample. A simple rule of thumb is also presented. Making an assignment using delta values is particularly useful when no other chemical profiling information is available. © 2013 American Chemical Society.

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