Mass spectrometer, system comprising the same, and methods for determining isotopic anatomy of compounds

A method for determining the isotopic composition of an analyte in a sample, the method comprising:

• using a first mass spectrometer comprising a single-collector and having a mass-resolution of about 30,000 or greater to measure ratios of ion beams at each cardinal mass of the analyte to produce first molecular analyte ion data;
• using a second mass spectrometer comprising a multi-collector to measure relative abundances of closely-adjacent ions at different cardinal masses of the analyte to produce second molecular analyte ion data;
• utilizing the first molecular analyte ion data to identify proportions of isotopologues that contribute to signal intensity at each cardinal mass measured with the second mass spectrometer;
• and
• utilizing the proportions of the isotopologues that contribute to the signal intensity at each cardinal mass to compensate for unresolved detected molecular analyte species and calculate an abundance of one or more isotopic species of interest measured with the second mass spectrometer.