Use of conjugates with linkers cleavable by photodissociation or fragmentation for mass spectrometry analysis of tissue sections

A method for determining at least one target molecule map in a tissue section, comprising:

• a) hybridizing said tissue section with at least one (A-X)-B conjugate, wherein
• A is a peptide tag molecule of known molecular weight,
• X is a linker that is cleaved during sample desorption/ionization,
• B is an antibody binding molecule that hinds specifically to said target molecule,
• each distinct B molecule is linked to a distinct A tag molecule, and
• said conjugate is of following formula:
• b) scanning the tissue section surface and analyzing each adjacent spot with a mass spectrometer, wherein said linker X is cleaved during sample desorption/ionization, and wherein the resulting data of each spot is saved;
• and
• c) analyzing the obtained data in the molecular mass window(s) of each distinct tag molecule to create as many maps of the tissue section as the number of distinct studied target molecules.