Peptide Sequencing With Electrospray Ionization On A Magnetic-Sector Mass-Spectrometer

Sequence information is obtained by in-source fragmentation of electrospray-generated peptide ions. The complete sequences of leucine enkephalin, angiotensin I, and renin substrate are determined from their fragment ions and consume only low picomole amounts of material. The method involves collision-induced fragmentation of singly and multiply charged molecular ions in the electrospray ion source and does not involve tandem mass spectrometric instrumentation. The charge on the fragment ions is determined by the spacing of the isotope peaks.