Analysis of peptides for detecting deamidation by LCMS with the QTrap 4000. For the three peptides that have deamidation sites, there are peaks corresponding to the unmodified form, the n-Asp form, and the isoAsp form of the asparagine residue in red. The unmodified form of each peptide elutes first, followed by the n-Asp form, and finally the isoAsp form. The first two deamidated peptides differ at the 8th position, where the first peptide has a leucine and the second peptide has a valine