An investigation into the ability of three analytical techniques to discriminate batches of methlamphetamine prepared by seven synthetic routes

This project evaluates the abilities of gas chromatography mass spectrometry (GCMS), isotope radio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry (ICPMS) to characterise methylamphetamine hydrochoride Repetitive batches of samples were prepared using seven synthetic routes commonly used by clandestine chemists (149 samples in total) and analysed by each technique to provide a robust sample set of known provenance for data interpretation. Organic analysis of all samples was undertaken using a developed and partially validated GCMS impurity profiling method. Basic and acidic impurities were extracted separately and analysed using a DB-1 MS column. The GCMS method discriminated all routes based on a set of route specific target impurities determined through this project. This target set was compared with suggested literature impurities and better resolution was achieved. Furthermore, variations in impurity profiles reported in the literature were resolved through investigation of the respective synthetic processes. A comparison of the DB-1 MS with a DB-5 column and a single basic pH extraction method confirmed this as a viable alternative to many of the methods described in the literature. Stable isotope ratios (δ¹³C,δ¹⁵N,δ²H) were measured by elemental analyzer/thermal conversion isotope radio mass spectrometry (EA/TC-IRMS). This facilitated the differentiation of samples by starting material, with δ¹³C providing the best results. Inorganic impurities present in the samples were analysed by inductive couple plasma mass spectrometry (ICPMS). This facilitated some discrimination of the samples by synthetic pathway only. Pattern recognition techniques were applied to the generated data (raw and processed) from each analytical technique both individually and together. Pearson's correlation coefficient, hierarchical cluster analysis, principal component analysis and discriminate analysis were used to investigate the separation of the sample batches by starting material and synthetic route. These mathematical tools demonstrated that methylamphetamine profiling linking samples by starting material and/or synthetic route was achievable.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2010

Author dc:creator

• Kunalan, Vanitha

DOI

10.48730/pf9c-ze43

Identifier

T12595

OAI identifier oai:identifier

oai:strathclyde:2227mp65f