Research Description: Prof. Matthews has been an analytical chemist and mass spectrometrist for over 30 years developing new methods for measurement of stable isotopically labeled biomolecules by mass spectrometry. The focus of his work has been use of the stable isotopes as tracers for measuring kinetic rates of metabolic processes in vivo and in vitro. Many of the methods developed have become standard methods in a variety of investigator laboratories and have been applied world-wide.