Detection and characterization of phosphopeptides by infrared multiphoton dissociation two-dimensional mass spectrometry (IRMPD 2DMS) is shown to be particularly effective. A mixture of phosphopeptides was analyzed by 2DMS without any prior separation. 2DMS enables the data independent analysis of the mixture and the correlation of the fragments to their precursor ions. The extraction of neutral loss lines corresponding to the loss of phosphate under IRMPD fragmentation allows the selective identification of phosphopeptides. Resonance of the 10.6 μm infrared radiation with the vibrational modes of the phosphate functional group produced efficient absorption and high cleavage coverage of the phosphopeptides at much lower irradiation fluence than for nonphosphorylated peptides improving discrimination. Additionally, the localization of the phosphate group was determined.
Due to the natural dispersity that
is present in synthetic polymers,
an added complexity is always present in the analysis of polymeric
species. Tandem mass spectrometry analysis requires the isolation
of individual precursors before a fragmentation event to allow the
unambiguous characterization of these species and is not viable at
certain levels of complexity due to achievable isolation widths. Two-dimensional
mass spectrometry (2DMS) fragments ions and correlates fragments with
their corresponding precursors without the need for isolation. In
this study, 2DMS electron capture dissociation (ECD) fragmentation
of a polyoxazoline and polyacrylamide species was carried out, resulting
in the analysis of byproducts and individual polymer species without
the use of chromatographic techniques. This study shows that 2DMS
ECD is a powerful tool for the analysis of polyacrylamide and polyoxazoline
species and offers a new dimension in the characterization of polymers.
Two-dimensional mass spectrometry
(2DMS) is a new, and theoretically
ideal, data-independent analysis tool, which allows the characterization
of a complex mixture and was used in the bottom-up analysis of IgG1
for the identification of post-translational modifications. The new
peak picking algorithm allows the distinction between chimeric peaks
in proteomics. In this application, the processing of 2DMS data correlates
fragments to their corresponding precursors, with fragments from precursors
which are <0.1 m/z at m/z 840 easily resolved, without the need
for quadrupole or chromatographic separation.
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