Illustration of chromatography metric C-2A applied to LC-MS/MS data from three Thermo LTQ systems in analyses of yeast proteome samples in CPTAC Study 5. Illustration of chromatography metric C-2A applied to LC-MS/MS data from three Thermo LTQ systems in analyses of yeast proteome samples in CPTAC Study 5. Time intervals for elution of the middle quartiles of peptide identifications (C-2A) are indicated as are values for C-2B (peptide identification rate during this interval) and total peptide identifications during the analysis (P-2C). See text for discussion. peps, peptides. Paul A. Rudnick et al. Mol Cell Proteomics 2010;9:225-241 © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.