Figure 3From: Efficient discovery of abundant post-translational modifications and spectral pairs using peptide mass and retention time differences2-D histogram of Δ m and Δ Rt for the carbamidomethylation modification found in data set 1. The sharp peak in both dimensions indicates the actual presence of this modification in the sample, since a modification must cause a fixed change in peptide mass and a slight shift in retention time.Back to article page