Rapid Qualitative Analysis of Synthetic Cathinones by Raman
Spectroscopy
HU Shuang1, LIU Cui-mei2*, XU Lin3, JIA Wei2, HUA Zhen-dong2
1. Beijing Police College, Beijing 102202, China
2. Key Laboratory of Drug Monitoring and Control, Drug Intelligence and Forensic Center, Ministry of Public Security, Beijing 100193, China
3. Yantai City Public Security Bureau, Marine Ecological Civilization and Economy Branch, Yantai 265800, China
Abstract：With the wide spread of new psychoactive substances (NPS) nationwide, it is an urgent need for the drug law-enforcing departments and relevant technicians to conduct an in-field rapid qualitative analysis of suspected NPS samples. Synthetic cathinones are cathinone derivatives and are the second-largest category of NPS. This study used a portable Raman spectrometer to analyze the Raman spectra of 70 synthetic cathinone reference substances.The Raman spectrum characteristics of synthetic cathinones were systematically summarized, which will help to identify the unknown synthetic cathinones. All analyzed synthetic cathinones showed strong bands at (1 597±19) and (1 676±16) cm-1, which was caused by the stretching vibration of the aromaticCC and CO bonds, and can be used to distinguish synthetic cathinones from other types of NPS. The benzene ring mono-substituted, and 1,3-disubstituted synthetic cathinones showed the most intense bands at 992~1 000 cm-1, caused by the in-plane deformation vibration of C—H on the benzene ring. 3,4-Methylenedioxy substituted synthetic cathinones showed strong bands at (712±9), (809±5), (1 250±16), (1 355±9), (1 444±12), (1 597±19), and (1 676±16) cm-1; meanwhile, shoulder-bands were observed around （1 597±19） cm-1. The overall discriminant ability of Raman for various regioisomers and structural analogues was also investigated. Raman spectra of 70 kinds of cathinones were compared one by one. Raman was generally distinguishable for most synthetic cathinones, especially for regioisomers substituted by the methyl, halogen and methoxy groups on the benzene ring. It is one of the significant advantages of Raman compared with GC-MS and LC-MS. Raman spectra of some structural analogues with different alkyl substitutions were highly similar but could also be distinguished by characteristic peaks. Raman was also used to analyze seized samples, and the results showed that when there was no fluorescence interference in the sample, the Raman database search result was consistent with that of GC-MS, which proved the high method reliability and applicability. The portable Raman spectrometer has the advantages of simple operation, fast and non-contact sample measurement, and can be used for the fast in-field preliminary qualitative screening of NPS.
[1] United Nations Office on Drugs and Crime (UNODC)-SMART: 1124 NPS Reported to UNODC From 134 Countries and Territories，2022.
[2] European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). European Drug Report 2021: Trends and Developments，2021.
[3] Soares J, Costa V M, Bastos M L, et al. Archives of Toxicology, 2021, 95(9): 2895.
[4] Valente M J, de Pinho P G, Basto M L, et al. Archives of Toxicology, 2014, 88(1): 15.
[5] Zaami S, Giorgetti R, Pichini S, et al. European Review for Medical and Pharmacological Sciences, 2018, 22(1): 268.
[6] La Maida N, Di Trana A, Giorgetti R, et al. Therapeutic Drug Monitoring, 2021, 43(1): 52.
[7] ZHAO Jing-you, WANG Yong, ZHANG Guan-nan(赵璟悠, 王 勇, 张冠男). Journal of Criminal Investigation Police University of China(中国刑警学院学报), 2018, (3): 116.
[8] Oliveira Penido C A F, Pacheco M T T, Lednev L K, et al. Journal of Raman Spectroscopy, 2016, 47, 28.
[9] LIU Cui-mei, HAN Yu, JIA Wei, et al(刘翠梅，韩 煜，贾 薇，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2020, 40(12): 3925.
[10] Jones L E, Stewart A, Peters K L, et al. Analyst, 2016, 141: 902.
[11] Guirguis A, Girotto S, Berti B, et al. Forensic Science International, 2017，273: 113.
[12] Liu C M, Xu Lin, He H Y, et al. Journal of Forensic Sciences, 2021, 66(1): 365.
[13] Christie R, Horan E, Fox J, et al. Drug Testing and Analysis, 2014, 6: 651.
[14] Stewart S P, Bell S E J, Fletcher N C, et al. Analytical Chimica Acta, 2012, 711: 1.
[15] LIU Cui-mei(刘翠梅). Handbook for the Analysis of New Psychoactive Substances (The Second Edition) Infrared Spectroscopy Parts[新精神活性物质分析手册（第2版）红外光谱分册]. Beijing: People’s Public Security University Press of China(北京：中国人民公安大学出版社)，2019, 9, 3.
[16] Socrates G. Infrared and Raman Characteristic Group Frequencies. John Wiley & Sons Ltd., Chichester, West Sussex, 2001.
[17] Mayo D W, Miller F A, Hannah R W. Course Notes on the Interpretation of Infrared and Raman Spectra. John Wiley & Sons Inc., Hoboken, New Jersey, 2004.
