Dottorato in SCIENZE CHIMICHE

Titolo della tesi: Advanced Methods for the Analysis of Chiral Pesticides and Emerging Organic Pollutants in Environmental and Biological Matrices

Emerging Organic Pollutants (EOPs) are organic chemical substances that have recently become a concern for environmental and human health due to their persistence in the environment, their tendency to bioaccumulate in living organisms, their potentially toxic effects even at low concentrations, and their resistance to conventional wastewater treatment methods. These pollutants include a wide range of compounds such as pharmaceuticals and personal care products, brominated flame retardants, hormones, perfluoroalkyl compounds, modern pesticides, nanomaterials, degradation products, UV filters, and microplastics. As these pollutants have only recently been recognized as a significant threat, their regulation is still developing in many parts of the world. Within the category of modern pesticides, chiral pesticides are of particular interest. Chiral pesticides exist as enantiomers, molecules that are mirror images of each other, and can have different biological activities and toxicities. Overall, while regulatory agencies are increasingly recognizing the importance of considering chiral properties in their assessments, a lot of effort still needs to be done in the evaluation of standardized guidelines and in the development of advanced analytical methods to accurately determine the enantiomeric composition and assess the differential effects. In this context, the focus of this doctoral thesis was to address these critical issues by exploring conventional and innovative approaches to sample preparation and high-throughput analytical method development to study the occurrence of EOPs and chiral pesticides in biological and environmental matrices. The thesis is organized into two main sections. The first section delves into EOPs, highlighting their primary sources and providing an overview of the main EOPs classes, their distribution across various environmental compartments, as well as their impacts and toxic effects on ecosystems, human, and animal health. The section also covers the most commonly used sample preparation and analytical techniques. This is followed by a chapter dedicated to an experimental application, specifically the development of a QuEChERS multi-analyte and multi-class method for EOPs in sea sand, a complex and unconventional matrix. The second section shifts focus to chiral pesticides, exploring their environmental degradation mechanisms, interactions between enantiomers and chiral selectors, and thermodynamic studies on enantiomeric complexes, with particular emphasis on the use of polysaccharide-based selectors for enantioselective separation. It also briefly discusses chiral analytical techniques in analytical chemistry, with a special focus on chiral liquid chromatography as a method to study the occurrence and fate of chiral pesticides in environmental matrices and agricultural products, which is extensively covered in a dedicated review chapter. This section is divided into two chapters, each focusing on a different experimental application. In particular, the first chapter discusses a sample preparation method based on carbonaceous sorbents to analyse human urine matrix, while the second chapter introduces a greener, more innovative method utilizing a microextraction technique based on a ferrofluid, applied to river water.