A method includes obtaining a first mass spectrum; selecting a first peak of the first mass spectrum; isolating precursor ions in an isolation window including the first peak; fragmenting and analyzing the isolated ions to obtain a second mass spectrum; performing a real-time search of the second mass spectrum for both the target precursor and near isobaric precursors ions that are co-isolated with the target precursor in an isolation window; adding the precursor ions that produced an identification during the real-time search to the exclusion list; selecting a second peak present in the first mass spectrum and not on the exclusion list; and fragmenting and analyzing ions of the second peak to obtain a third mass spectrum.