The main project of the unit is the development of efficient, specific, and sensitive methodologies for the identification, quantification, and molecular characterization of proteins, peptides, and other peptidomimetic molecules such as certain toxins, as well as the study of their modifications. We have recently focused on specific modifications such as glycosylations and oxidation-reduction phenomena. The analysis of proteins in proteomic studies can be done directly on the whole protein object (top-down analysis of the proteoforms of interest) or elements of it either after controlled proteolysis (middle-down analysis) or the proteolytic peptides after complete proteolysis (bottom-up analysis). It generally combines separation and enrichment steps. The emergence of mono (1D LC) or multidimensional (2D LC) liquid nano-chromatographic techniques coupled with tandem mass spectrometers (MS/MS) equipped with nanoESI sources, such as hybrid instruments combining multipole analyzers (quadrupole or Linear ion traps) with high-resolution TOF (Time-Of-Flight) or very high-resolution FT Orbitrap analyzers (such as the 1M resolution Orbitrap analyzer fitted to the Eclipse tribrid mass spectrometer), are attractive approaches due to their ability to fragment peptides present in minimal quantities, in order to obtain amino acid sequence information. This coupling can be supplemented by other separation strategies such as ionic mobility, which in most cases eliminates the separation step by two-dimensional electrophoresis, which was historically used. Various modes of fragmentation are often necessary and must be combined to characterize all the proteins and their post-translational modifications directly from mixtures. We thus work by associating CID, HCD, ETD, UVPD, or even CID and PSD. MALDI mode ionization can also be implemented in LC-MS/MS analysis to generate sequence information directly from preparations used to establish peptide maps. This ionization mode is also essential for carrying out glycomic studies and makes it possible to obtain detailed maps. Since mass spectrometry is not a quantitative method per se, another aspect of the work carried out in the laboratory is the development of stable isotopic labeling methods or even strategies to obtain qualitative and quantitative information on the level of expression of proteins and the occupancy rate of post-translational modifications. Finally, for some years, we have undertaken a growing effort for the integration of microfluidic methods in order to increase our overall sensitivity by limiting the major losses of information and material due to the manipulation of the sample, which is nowadays the main bottleneck for proteomics applications that suffer from a lack of signal amplification techniques.