Comparative study of the analysis of seized samples by GC-MS, 1H NMR and FT-IR spectroscopy within a Night-Time Economy (NTE) setting

Dixon, David I, Antonides, Lysbeth H, Costello, Andrew, Crane, Benjamin, Embleton, Arran, Fletcher, Mark L, Gilbert, Nicolas, Hulme, Matthew C, James, Molly J, Lever, Michael A, Maccallum, Conner J, Millea, Molly F, Pimlott, Jessica L, Robertson, Thomas BR, Rudge, Nathan E, Schofield, Christopher J, Zukowicz, Filip, Kemsley, E Kate, Sutcliffe, Oliver ORCID: https://orcid.org/0000-0003-3781-7754 and Mewis, Ryan E (2022) Comparative study of the analysis of seized samples by GC-MS, 1H NMR and FT-IR spectroscopy within a Night-Time Economy (NTE) setting. Journal of Phamaceutical and Biomedical Analysis, 219. p. 114950. ISSN 0731-7085

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Abstract

Rapid analysis of surrendered or seized drug samples provides important intelligence for health (e.g. treatment or harm reduction), and custodial services. Herein, three in-situ techniques, GC-MS, 1H NMR and FT-IR spectroscopy, with searchable libraries, are used to analyse 318 samples qualitatively, using technique specific library-based searches, obtained over the period 24th – 29th August 2019. 259 samples were identified as consisting of a single component, of which cocaine was the most prevalent (n = 158). Median match scores for all three techniques were ≥0.84 and showed agreement except for metformin (n = 1), oxandrolone (identified as vitamin K by IR (n = 4)), diazepam (identified as zolpidem by FT-IR (n = 2)) and 2-Br-4,5-DMPEA (n = 1) a structural isomer of 2C-B identified as a polymer of cellulose (cardboard) by FT-IR. 51 samples were found to consist of two or more components, of which 49 were adulterated cocaine samples (45 binary and 4 tertiary samples). GC-MS identified all components present in the 49 adulterated cocaine samples, whereas IR identified only cocaine in 88% of cases (adulterant only = 12%). The breakdown for 1H NMR spectroscopy was all components identified (51%), cocaine only (33%), adulterant only (10%), cocaine and one adulterant (tertiary mixtures only, 6%).