Updated project metadata. Fast photochemical oxidation of proteins (FPOP) is a modern technique for studying protein folding, conformations, interactions, etc. In this work, timsTOF Pro mass spectrometer coupled with trapped ion mobility spectrometry was used for identification of oxidative modifications in a model protein. Multiple modifications on the same residues, including six modifications of histidine, were successfully resolved. Moreover, PASEF technology allows successful sequencing even minor populations of modified peptides.