The TSQ Altis Plus mass spectrometer delivers high accuracy and precision for low-level compound targeted detection and quantitation in complex matrices. It is characterized by ultrafast selected-reaction monitoring (SRM), optimal selectivity with high-resolution (0.2 Da FWHM) selected-reaction monitoring (H-SRM) performance to improve signal-to-noise ratios for targeted compounds providing robust, reliable, and sensitive targeted quantitation ideal for pharmacokinetics analysis.