Mass spectrometers 40 Mass spectrometry 34 article 28 controlled study 18 mass spectrometry 16 priority journal 16 Electrospray ionization 14 Spectrometry 14 Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization 14 electrospray mass spectrometry 14 Ionization 12 Spectrometry, Mass, Electrospray Ionization 12 matrix assisted laser desorption ionization time of flight mass spectrometry 12 nonhuman 12 time of flight mass spectrometry 12 Desorption 10 chemical structure 10 Animals 8 Electrospray ionization mass spectrometry 8 Inductively coupled plasma mass spectrometry 8 Mass Spectrometry 8 Positive ions 8 Spectrum analysis 8 carbohydrate analysis 8 unclassified drug 8 Amines 6 Argentina 6 Article 6 Carbohydrates 6 Electrosprays 6