Dottorato in SCIENZE CHIMICHE

Titolo della tesi: Mass spectrometry: high and low resolution. From targeted to untargeted analysis in environmental matrices for the determination of persistent and emerging contaminants and their transformation products.

In recent years, the advances in mass spectrometric instrumentation have significantly expanded, especially in environmental analysis. In this field, High Resolution Mass Spectrometry (HRMS) plays a fundamental role when dealing with trace analytes within complex matrices, which is still an analytical challenge. Hence, advances in mass spectrometry technology, coupled with chromatographic techniques, have made it possible to identify and quantify such molecules. Moreover, environmental research brings various challenges, such as dealing with the complexity of the samples due to the presence of a vast number of both natural and anthropogenic compounds. Furthermore, the analytes of interest are often present in trace amounts, necessitating the handling of substantial sample quantities and the implementation of enrichment and purification methodologies. Eventually, to achieve reliable compound identification, the optimization of an analytical platform based on chromatographic instrumentation coupled with HRMS is imperative. When characterizing environmental matrices, it is important to consider the presence of numerous contaminants and pollutants. Specifically, analytical scientists are dealing with persistent organic pollutants (POPs) and contaminants of emerging concern (CECs). CECs are substances recently introduced into the environment or known to exist but previously unrecognized as hazardous to ecosystems. Some of them have been present for a long time but have only been detected recently due to improved analytical techniques. CECs encompass pharmaceuticals, personal care products (PPCPs), hormones, UV filters, UV stabilizers, pesticides, plasticizers, illicit drugs, and various industrial chemicals, along with their transformation products. Many transformation products lack commercially available analytical standards, and for some compounds, their presence is only suspected or entirely unknown. In such cases, the use of HRMS xii surely offers several advantages: simultaneous determination of all compounds in the sample without the need for predefined standard analyte selection, the ability to perform suspect and untargeted analyses, and the identification of unknown compounds with the assistance of software. Additionally, the vast amount of stored data, including full scans and fragmentation spectra, allows for retrospective analysis. In the environment, only a tiny fraction of compounds are monitored, and a subset of these are subject to regulation. Hence, it is important to have efficient techniques for monitoring the presence of CECs in environmental matrices. This thesis work aims to provide a better understanding of the three main approaches for the analysis in the environmental field. The studies were divided into three main sections: targeted, suspect, and untargeted approaches. In each section, one of the three main approaches used in environmental analysis has been studied for its application in this field on different matrices.