Emerging drugs addiction: NIR spectroscopy and chemometrics for the early detection of new psychoactive substances

Near infrared spectroscopy (NIRs) proved to be a fast and non destructive tool for the detection of different compounds in forensic matrices [1]. This study investigated the feasibility of using NIR coupled to chemometrics calibration to detect new psychoactive substances in street samples. The capabilities of this approach in forensic chemistry were assessed in the determination of new molecules appeared in the illicit market and often claimed to contain “non-illegal” compounds, although exhibiting important psychoactive effects. The study focused on synthetic molecules belonging to the classes of synthetic cannabinoids, phenethylamines and cathinones. For each sample, NIR spectra in reflectance mode were acquired and chemometric tools based on Principal Component Analysis (PCA) were used to built a multivariate model of prediction for the screening of new emerging substances. The approach was validated comparing results with officials methods and successfully applied for “in site” determination of illicit drugs in confiscated samples, in cooperation with the Italian Scientific Investigation Department (Carabinieri RIS) of Rome. The achieved results allow to consider NIR spectroscopy analysis followed by chemometrics as a fast, cost-effective and useful tool for the preliminary determination of new psychoactive substances in forensic science.