Alzheimer's disease is characterised by brain neuritic plaques composed of a 39-44 amino acid peptide (Abeta). Lipid peroxidation is an early event induced by these amyloid beta-peptides, leading to the formation of 4-hydroxy-2-nonenal (HNE), which is one of the major end products of this process. HNE has been reported to form adducts via a stable covalent binding to proteins through a Michael addition to amino acid residues with a nucleophilic side chain. The present study reports an investigation of the conditions for formation of Abeta-HNE (Abeta 1-28 and Abeta 1-42) adducts, and their characterisation by liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS). The results suggest that one or more HNE moieties are localised in the 6-16 region of these adducts, while Asp-1, Lys-16 and Lys-28 are not modified under the described reaction conditions.

In this research paper, we report a hyphenated technique based on ultra-high performance liquid chromatography–tandem mass spectrometry for the determination of twelve Perfluorinated Alkylated Substances in surface and groundwater samples from Lombardia Region during the monitoring activities in 2018 as new emerging and toxic pollutants. A green analytic method, developed by using an online Solid Phase Extraction coupled with UHPLC-MS/MS and previously validated, was applied for 4992 determinations conducted on 416 samples from 109 different sampling stations. Among the results, PFOS, PFOA, PFBA, PFBS, PFPeA and PFHxA were identified as the most abundant analytes detected. PFASs concentrations, in most cases, were below the limits of quantification and, in the cases where the limits of quantification have been exceeded, the values found were lower than Italy directive. PFOS is an exception and in fact this compound was detected in 76% of analyzed samples (surface and ground waters). Solid phase extraction with high performance liquid chromatography–tandem Mass Spectrometry has proved to be a very good Hyphenated techniques able to detect low concentrations of pollutants in surface and groundwater samples.