Identification of new psychoactive substances (NPS) by Raman spectroscopy

摘要

There is an increasing need of developing methods for fast recognition and identification of new psychoactive substances (NPS). The chemical identification of these new substances produced with the intention of mimicking the effects of controlled drugs is a challenge for forensic and Customs laboratories. In this study, we aim to test the potential of Raman spectroscopy for the identification and classification of seized Customs samples into three NPS families. The performance of two excitation wavelength lasers (785 and 1064 nm) in a benchtop Raman instrument was compared in a set of seized samples that included cathinone, fentanyl, and synthetic cannabinoid derivatives or analogues. The 1064 nm wavelength laser had significant advantages for identifying NPS samples overcoming the intense fluorescence induced when using 785 nm lasers in some substances. Principal component analysis was employed to create a model that successfully discriminates the three NPS families. In order to provide Customs officers with a fast and nondestructive in-field testing method, the same approach used with the benchtop Raman spectrometer was applied using three handheld Raman instruments. The developed identification and classification model allows the discrimination of fentanyl, cathinone, and synthetic cannabinoid analogues or derivatives providing an efficient tool for the rapid identification of three NPS families. The approach presented in this study can facilitate rapid decision-making that could be of high relevance especially in the frame of the fentanyl crisis.