Patent ID: 7186973

Claim:
A mass analyzing method for use in an ion trap/time-of-flight mass analyzing apparatus including an ion source for ionizing a measurement sample, an ion trap having a ring electrode and a pair of end cap electrodes and trapping ions produced by said ion source therein, and a time-of-flight mass spectrometer, said method comprising the steps of: ionizing sample ions having known mass numbers; applying DC voltage to said ring electrode and end cap electrodes; measuring mass numbers of said sample ions passing through said ion trap by said time-of-flight mass spectrometer; calibrating said time-of-flight mass spectrometer by comparing measured mass numbers of said sample to said known mass numbers; supplying sample ions having known mass numbers to said ion trap; trapping said sample ions in said ion trap; expelling unwanted ions out of said ion trap; expelling ions remaining in said ion trap to said time-of-flight mass spectrometer; measuring mass number of remaining ions expelled from said ion trap by said time-of-flight mass spectrometer; and calibrating control parameter of said ion trap by using mass numbers measured by said time-of-flight mass spectrometer.