update LabHead Dataset QC1 was acquired to elaborate the transition groups for the proteotypic peptides of 21 human proteins encoded by chromosome 18. Preliminary transition groups were extracted from the results of MRM scouting of depleted plasma and liver and organized into 9 MRM assays by groups named A to E with least overlapping of RT-window of proteotypic peptides separately for light (L) and heavy (H). Decoy transitions were generated for each assay by ADD_RANDOM algorithm of mGen. Data acquisition for each assay was conducted using the synthetic peptide mixtures in five technical runs on the triple-quadrupole mass-spectrometer.