Detection, discrimination and quantification of amphetamine-, methcathinone-, ethcathinone- and norephedrine-regioisomers using benchtop 1H and 19F NMR spectroscopy

Hulme M,Hayatbakhsh1 A,Brignall R,Gilbert N,Costello A,Schofield C,Williamson D,Kemsley K,Sutcliffe O,Mewis R. (2021)

Magnetic Resonance in Chemistry

Amphetamine and cathinone derivatives are abused recreationally. Derivatisation of these drugs occurs to circumvent global and local drug laws. Synthesis of regioisomers is one such derivatisation route. Discrimination of individual amphetamine-, methcathinone-, ethcathinone and norephedrine-derived fluorinated and methylated regioisomers is achieved herein using qualitative automated ¹H NMR analysis and compared to GC-MS data. Two seized drug samples, SS1 and SS2, were identified to contain 4-fluoroamphetamine by ¹H NMR (match score median = 0.9933) and GC-MS (RR_t = 5.42-5.43 min). The amount of 4-fluoroamphetamine present was 42.8-43.4% w/w and 48.7-49.2% w/w for SS1 and SS2 respectively from quantitative ¹⁹F NMR analysis, which is in agreement with the amount determined by GC-MS (39.9-41.4% w/w and 49.0-49.3% w/w). The total time for the qualitative ¹H NMR and quantitative ¹⁹F NMR analysis is ca. 10 min. This contrasts to ca. 40 min for the GC-MS method. The NMR method also benefits from minimal sample preparation.

Magnetic Resonance in Chemistry

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