Abstract: Methods and systems for obtaining mass spectrographic data of a substance. Methods include subjecting a substance to a chromatographic process or other separating process, ionizing the output thereof, and subjecting the ionized output to recursive mass spectrometry analyses; and provide improved processing and analysis of data acquired during the repeated analyses. Systems according to one aspect of the invention comprise ion sources, mass spectrometers capable of analyzing ions of selected mass, and controllers adapted to receive from the mass spectrometers and retain signals representing data representing pluralities of mass spectrograms. The controllers can be adapted to generate information useful for describing extracted ion chromatograms, using data associated with the pluralities of mass spectrograms and non-linear curve approximation algorithms; and to use the generated information to generate further information useful in further analysis of the ionized substance.