The relative mass spectral intensity of natural isotopologues, calculable from the fractional abundances of the constituent elements, is exploited by mass spectrometry practitioners in quantitative analysis and unknown compound identification:
# To identify the more likely molecular formulas for an unknown compound based on the matching between the observed isotope abundance pattern in an experiment and the expected isotope abundance patterns for given molecular formulas.
# To expand the linear dynamic response range of the mass spectrometer by following multiple isotopologues, with an isotopologue of lower abundance still generating linear response even while the isotopologues of higher abundance giving saturated signals.