In various areas of research, proteomics and particularly the quantification of proteins and peptides renders a useful addition to biochemical experiments. The range of possible applications varies from supervision of concentration changes of relevant proteins during biogenesis to differential proteomics approaches, distinguishing, for instance, healthy and diseased states. Furthermore, mass spectrometry-based peptide quantification yields the possibility of using highly sensitive bottom-up approaches for determination of protein regulations as well as multiplexing capability. Thereby, changes in protein abundances may be linked to specific cellular states bearing the opportunity to reveal marker proteins for several diseases.