Fragment correlation mass spectrometry: determining the structures of biopolymers in a complex mixture without isolating individual components

Fragment correlation mass spectrometry correlates ion pairs generated from the same fragmentation pathway, achieved by covariance mapping of tandem mass spectra generated with an unmodified linear ion trap without pre-separation. We enable identification of different precursors at different charge states in a complex mixture from a large isolation window, empowering a new analytical approach for data-independent acquisition. The method resolves and matches isobaric fragments, internal ions, and disulfide bond fragments.