matrix effect Article 6 controlled study 6 liquid chromatography-mass spectrometry 5 drug determination 4 limit of quantitation 4 multiple reaction monitoring 4 unclassified drug 4 animal experiment 3 animal tissue 3 area under the curve 3 male 3 nonhuman 3 time to maximum plasma concentration 3 Pharmacokinetics 2 acetic acid 2 acetonitrile 2 ammonium formate 2 chromatography 2 comparative study 2 drug absorption 2 drug bioavailability 2 drug half life 2 electrospray mass spectrometry 2 human 2 limit of detection 2 mass spectrometry 2 maximum concentration 2 measurement accuracy 2 methanol 2