The low energy loss spectroscopy interpretes the signal resulting from the excitation of the valence or conduction electrons of a material under the impact with an electron beam. The analysis of this signal in terms of plasmon energy, low-loss function or dielectric function gives a lot of informations about the electronic structure and the chemical bonding of the sample. When this spectroscopy is connected with a field emission gun scanning transmission electron microscope (STEM-VG HB5O1) it constitutes a very relevant tool to solve material problems for which nanoanalytical investigations are of prime importance. These performances are illustrated by three examples.