Multiple reaction monitoring (MRM) based targeted quantification is becoming quite popular in the proteomics community, as this approach is able to replace expensive antibody-based quantification like Western blotting and ELISA. MRM performed on QTOFs and Orbitraps are called parallel reaction monitoring (PRM). In PRM, post mass spectral acquisition, extracted ion chromatograms (XIC) for selected ions are used for quantitation. The high scan speed facilitates development of sequential window acquisition of all theoretical mass spectra (SWATH). In this approach, peptides are quantitated by targeted data extraction of SWATH-MS data.