Photodissociation of singly protonated peptides at 193 nm investigated with tandem time-of-flight mass spectrometry.

Photodissociation at 193 nm of some singly protonated peptides generated by matrix-assisted laser desorption/ionization was investigated using tandem time-of-flight mass spectrometry. For peptides with arginine at the C-terminus, x, upsilon, and w fragment ions were generated preferentially while a and d fragment ions dominated for peptides with arginine at the N-terminus. These are the same characteristics as photodissociation at 157 nm reported previously. Overall, the photodissociation spectra obtained at 157 and 193 nm were strikingly similar.