1. In situ characterization approaches

Unlike most biochemical analyses, which involve compound extraction and, at the very least, grinding of the solid sample, in situ characterization methods allow us to characterize the sample in its initial state. These approaches have the advantage of preserving the structure and composition of the sample, and providing access to the distribution of analyzed compounds within the sample. Imaging approaches provide information on the morphology of the objects observed (tissues, cells, organelles, etc.) and on their chemical composition, including in some cases their molecular structure (figure 1 ).