DETERMINATION OF PEPTIDE SEQUENCES

An apparatus and process are used to cyclicly degrade a peptide to be sequenced, arriving at a set of amino acid residues for each cycle. The amount of each amino acid residue is quantitatively measured in each set, then a background level is fit to each cycle to obtain a background fit. A measure of dispersion is then calculated for the background fit, and the measured amounts of amino acid residues in each cycle are normalized relative to the background fit. The largest normalized background-corrected residue amount in each cycle then provides a sequence assignment that can be used for further correction steps if desired.