"Atherosclerosis is a chronic inflammatory response, clinically asymptomatic in the first decade. The deposition of lipids in arterial walls, due to the uptake of oxidized low density lipoproteins (oxLDL) by macrophages, causes blood flow restriction making cardiovascular diseases (CVD) a serious public health problem in EU countries. In oxLDL, oxidation of (phospho)lipids and proteins occurs, originating phospholipids-protein adducts by cross-linking reactions. Though phospholipid-protein adducts were identified in atherosclerotic plaques by immunoassays, their structural features were not yet described. It is known that smaller and denser (SD) oxLDL is more atherogenic, but the mechanism is yet unclear. Improved understanding of the pathology and potential therapies depends on molecular characterization of atherogenic LDL particles including the phospholipid-Apo B (PL-Apo B) adducts. To achieve this, mass spectrometry based strategies will be used to characterize PL-Apo B adducts in SD oxLDL from healthy and diseased clinical samples. The methodological approach will be developed in control LDL in vitro oxidized (HOCl, MPO, Me+H2O2) to determine the nature of PL-Apo B adducts formed, followed by biotinylation and separation by avidin magnetic beads of PL-Apo B adducts for optimization of PL-Apo B adducts isolation protocols with high specificity and sensitivity. Detection through MS strategies (MRM, CID) avoids time consuming analysis by a focused detection approach. Subsequently, the optimized approach will be applied to LDL from clinical samples in search of PL-Apo B adducts. The data from clinical samples will be scrutinized by chemometric techniques for discriminant ions prior to full characterization. This study will contribute to the molecular understanding of CVD pathology. The development of advanced methods for routine analysis will enable identification of new biomarkers for early clinical diagnosis."