Titolo della tesi: Development of spectroscopic and chromatographic techniques for the determination of drugs and other materials in the fight against illicit trafficking and commercial fraud
In these three years of work for my PhD, the orientation has been towards the development and optimization of the MicroNIR/Chemometrics, which can be used as a rapid screening tool in the context of first level controls of customs activities, a platform to support customs activities and, potentially, also law enforcement in their activities such as checks and controls at operational customs and at warehouses of substances of fiscal interest. In carrying out the checks, the first objective is to determine and characterize a certain substance and establish the need to investigate its nature, for the competent authorities one of the key elements is to optimize the time required to have a real-time response. The added value of portable NIR coupled with chemometrics lies in the possibility of bringing the laboratory into the field, allowing direct acquisitions on the object under examination and allowing for a rapid response.
This implementation could assist law enforcement personnel in making rapid decisions on whether or not to proceed with certain samples and substances, possible in-depth analyses and judicial measures.
The fields I focused on are to the main competences which involve the ADM chemical laboratories: 1) seized drugs containing the most diffuse active principles (Cocaine, Heroin, THC), in cooperation with Italian Police Forces (Polizia, Carabinieri, Guardia di Finanza), with the coordination of Procura Della Repubblica; 2) gasoil fuels with the overlook on compliant and non-compliant diesel fuels, because is an emerging field of interest for Criminal Organizations for tax evasion and recycle of pollutant solvents destinated as special waste18; 3) textiles products, testing if the model is able to distinguish pure fibers, engaging the main 100% animal, vegetal and synthetic fiber textiles, and, subsequently, applying the analytical protocol on polyester containing textiles to quantify this fiber because is the main fiber used in textiles’ fraud8,9,10.
For each field of interest, the initial step consisted of performing the analyses according to the official reference methods, then acquiring the spectra with the MicroNIR and subsequently processing the spectra matrix with the software called Unscrambler, then running a data exploration with PCA (Principal Component Analysis) to catch if a correlation between samples is possible, and then performing a regression model as the PLSDA on the chosen matrices for classification purposes or the PLS for quantification purposes.
The results that have been obtained demonstrate rapid, non-destructive identification, eliminating the need for sample pre-treatment and thus avoiding the use of solvents. Furthermore, the simplicity of this approach makes it accessible to non-expert personnel, requiring only adequate training.