mass spectrometry article 194 nonhuman 122 priority journal 92 unclassified drug 92 controlled study 82 chemistry 68 Animals 56 metabolism 56 Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization 54 Humans 50 human 50 Mass Spectrometry 48 Mass spectrometry 44 proton nuclear magnetic resonance 44 Article 38 chemical structure 36 carbon nuclear magnetic resonance 34 animal 32 methodology 32 Argentina 30 Molecular Structure 30 matrix assisted laser desorption ionization time of flight mass spectrometry 30 nuclear magnetic resonance 30 drug isolation 28 gas chromatography 28 nuclear magnetic resonance spectroscopy 28 high performance liquid chromatography 26 in vitro study 26 physiology 26