Reactive Metabolism and New Screening Methodology Using Exact Mass Neutral Loss Uplctm/ms/ms

moiety, which can be monitored (Figure 1). However, this methodology can result in many false positives due to the nominal mass characteristic of these instruments. To eliminate this false positive potential, the extra selectivity and sensitivity of exact mass neutral loss measurement using a hybrid quadrupole time-of-flight mass spectrometer can be an attractive alternative. Additionally, full scan MS information is retained for further exploration to confirm the presence of the GSH adduct or other metabolites of interest. In this study, we will demonstrate the use of exact mass neutral loss mode with the Waters® Micromass® Q-Tof PremierTM Mass Spectrometer for the UPLC/MS analysis of GSH adducts in in vitro samples. The resulting exact mass measurement yielded unequivocal results, confirming all reactive metabolites with errors less than 3 ppm RMS.