Patent ID: 8173957

Claim:
A method of identifying a multiply-charged ion comprising: a) specifying a digital signal threshold on a mass spectrometer, wherein the mass spectrometer comprises: i) an ion detector; ii) a digitizer for converting an analog signal to a digital signal; iii) an analog signal transfer means for transferring an analog signal from the detector to the digitizer; and iv) a digital threshold filter, for setting a digital signal threshold, in digital data communication with the digitizer, in response to a digital signal input from the digitizer, independently outputting a digital signal to a data file only if the digital signal input is greater than the specified digital signal threshold; wherein upon a mass spectrometer measurement of the multiply-charged ion, the filtered digital signal output to the data file originates from the detection of the multiply-charged ion and excludes digital signal output from analog signals arising from singly-charged ions.