The LCMS-IT-TOF Liquid Chromatograph/Mass Spectrometer, a novel hybrid mass spectrometer for biomarker discovery, metabolite identification, and proteomics research, couples atmospheric pressure ionization with Ion-Trap (IT) and Time-of-Flight (TOF) technologies to deliver high mass accuracy and high mass resolution (10,000 at 1000 m/z) independent of MS mode. The ion trap is not only used to focus ions before ejection into the TOF, but it also supports fragmentation, MSⁿ analysis and a high precursor ion selection (resolution >1;,000 at 1,000 m/z). A high precursor ion selection allows specific ions to be isolated for further fragmentation, simplifying MS/MS data interpretation and enhancing the selectivity of detection, particularly from complex matrices. The instrument incorporates fast polarity switching speed (100 ms to switch between positive and negative ionization) combined with Compressed Ion Injection (patented), Ballistic Ion Extraction (patent pending), and Dual-Stage Reflectron (patent pending) technology.