Sviluppo di nanotecnologie innovative nel campo della cromatografia liquida e della spettrometria di massa

The PhD project is focused on applying innovative nanotechnology in the field of liquid chromatography- mass spectrometry and the sampling and preparation of analytical samples. The main objective of the research was the improvement of the experimental interface LC-MS Direct-EI in the analysis of compounds with high molecular weight and high boiling point like 17-α-ethinylestradiol, 17-β-estradiol, indeno(1,2,3 c- d)pirene. In previous analyses, these compounds remained immobilized on the metal surface of the ionization source, providing inadequate results. An innovative solution was the application of a thin layer of a nano-ceramic or other coatings, made with sol-gel technique, on the internal surface of the ion source. An example of these coatings are TEOS (tetra ethoxy ortho silicate), Titania, and Zirconia. The excellent results obtained, with the nano-ceramic first and with the silicon-based coverage then, suggest to continue research on new sol-gel coatings to increase the number of analyzable substances with a common electron ionization source, specifically with Direct-EI. The second point of the project shows the benefits of nanotechnologies in the preparation of analytical samples, like the use of the MEPS (micro extraction by packed sorbent) and the MIMS (membrane introduction mass spectrometer). The first technique, combined with an UHPLC-UV-Vis detector, was applied to determinate 5 benzodiazepines in an alcohol beverage, in a single step (purification and extraction together) and with a small amount of original sample. These results were achieved without losing efficiency. MEPS is therefore suitable to be used in forensic investigations. The MIMS, silicone membranes with a thickness of up to 500 nanometers, was combined with the Direct-EI. The interface between the two techniques was not immediate and it was necessary to reduce the flow rate to the order of nanolitres/min. The validation of the method was conducted by analyzing aqueous solutions of polycyclic aromatic hydrocarbons (PAHs). The obtained data have confirmed the utility of the new CP-MIMS-EI interface both in terms of efficiency and in terms of cost and analysis time. It is an interface that allows on-line, real-time, and in situ analysis. The last point of this project is a collaboration in a GC-MS/MS application to confirm the presence of 20 organochlorine pesticides, two organophosphate pesticides, boscalid, and bisphenol A, in human brain tissues. The 14 samples were collected from Sudden infant death syndrome (SIDS) and sudden intrauterine unexpected death syndrome (SIUDS) victims. The presence of several of the selected compounds was confirmed.