Patent ID: 8067728

Claim:
A method for improving selectivity of a measurement from a mass spectrometer, comprising: acquiring a plurality of mass spectra of a material over a period of time; selecting a first extracted ion current window and calculating from the plurality of mass spectra a first intensity as a function of time for an ion using the first extracted ion current window; selecting a second extracted ion current window and calculating from the plurality of mass spectra a second intensity as a function of time for the ion using the second extracted ion current window, wherein the first extracted ion current window comprises a first center position, the second extracted ion current window comprises a second center position, and the first center position is not equal to the second center position; comparing a first signal-to-noise ratio of the first intensity with a second signal-to-noise ratio of the second intensity; and if the second signal-to-noise ratio is greater than the first signal-to-noise ratio, using the second intensity for the measurement.