Fig. 1

a Schematic outline of a linear matrix-assisted laser desorption ionization (MALDI)–time-of-flight (TOF) mass spectrometer (MS). During the measurement process, the molecules of the examined sample are ionized, vaporized and finally analyzed by their respective time-of-flight through an electric field. This process generates a plot (mass spectrum) having mass-to-charge ratio (m/z) on the x-axis and intensity (ion count) on the y-axis. b Typical mass spectrum for a mass range of 1500–10.000 Dalton. c Example of a disease fingerprint, created by comparing mass spectra from a healthy and a diseased individual