1921104 MALDI-TOF MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry 5830 3766492 MALDI-TOF matrix-assisted laser desorption/ionization time-of-flight 2551 3362929 MALDI-TOF-TOF matrix-assisted laser desorption/ionization-time of flight 22 3738901 MALDI/TOF matrix-assisted laser desorption ionization/time-of-flight 14 2321528 MALDI matrix-assisted laser desorption/ionization time-of-flight 5 3766496 MALDI - TOF matrix-assisted laser desorption/ionization-time of flight 1