The mass-spectroscopic analysis of mixtures of gases is based on the fact that a given component contributes to a given peak independently of the other components. In other words these contributions are additive, and the total peak height is the sum of all contributions from the components that form an ion that gives such a mass to charge ratio. Generally for any peak, the height is given by the expression:
H - the height of the peak
p - the partial pressure of a component in the mixture
r - the relative intensity of the ion resulting from a given component; the values are obtained from the mass spectra of pure samples of the components of the unknown mixture, and
s - the sensitivity factor for a given component; determined from the mass spectra of the individual components
When the r and s values have been determined, the analysis of an unknown mixture can be performed by forming a set of simulatenous equations from the peak heights. For an n component mixture, n equations are necessary, or only n peaks of all the avilable peaks are needed.
This will be illustrated on a three component mixture: