Geographical spread and analytical approach in the determination of new psychoactive substances

New psychoactive substances (NPS) are alleged drugs deriving from alterations of the chemical structures of currently regulated widespread drugs of abuse, such as MDMA. Those compounds can be classified according to several parameters, among which the chemical framework, resulting in a few crucial classes, namely phenethylamines, piperazines, synthetic cannabinoids and synthetic cathinones. The purpose of this thesis is to assess the analytical approach applied to those substances. Owing to a number of reasons, such as their transient nature, failure of detection on routine urine drug screening and attractive names, NPS are effortlessly and legally sold online, in the darkweb, and in head shops, appealing to 2,9 million people aged 15-24 in the EU from 2013 onwards. The United Nations Office on Drugs and Crime (UNODC) established the Early Warning Advisory (EWA) in an attempt to monitor the emergence of such drugs and pose a constraint on their rapid development, considering that roughly 50 to 100 new psychoactive substances are crafted each year, accounting for close to 71000 seizures in 2016 in the EU. A few promising policies and regulations have been implemented globally, ranging from individual listings and analogues control to total bans and leading to several NPS being nowadays placed under international control. Analogously to the drug checking path for common illicit drugs (ID), NPS undergo a preliminary screening followed by a confirmatory test, which, in the case of IDs, are routinely done by colorimetric reagents, high-performance liquid chromatography (HPLC), gas chromatography coupled to a mass spectrometer (GC-MS), immunoassays or further biochemical procedures, for instance the enzyme-linked immunosorbent assay (ELISA). However, such established approaches prove to be ineffective in most NPS cases, due to the discrepancy in the chemical composition and concentration of drug samples. That being said, NPS fail to be detected in the screening step and false positive results emerge. Further scientific challenges include the lack of timely-crafted reference standards, the limited availability of analytical standards, the unclear extensive metabolism in various matrices, the insufficient information on chromatographic patterns and spectral features and, lastly, matrix effect in techniques involving mass spectrometry. In order to overcome those setbacks, a range of procedures can be applied, including the highly performant liquid chromatography tandem (high resolution) mass spectrometry (LC-HRMS/LC-MS), due to its versatility, high resolution, accurate-mass full-spectrum acquisition and spatial separation combined to an unmistakable compound identification. As far as the matrix is concerned, urine still represents the standard and most suitable specimen for drug checking techniques, owing to the relatively high concentration of drugs and metabolites, even though limitations posed by an extensive metabolism may occur. In conclusion, the analytical approach to NPS is undoubtedly complex, but progresses are continuously made, in an effort to ensure forensic and toxicological preparedness in facing this emerging challenge.