Patent ID: 7569813

Claim:
A method of operating an ion trap spectrometer system having an ion trap, the method comprising; a) providing a group of ions for analysis, wherein the group of ions includes a first analyte; b) providing a filtered first analyte having a first mass-to-charge ratio by filtering out ions other than the first analyte; c) storing the filtered first analyte in the ion trap; d) storing a first set of calibrant ions in the ion trap with the filtered first analyte, wherein the first set of calibrant ions has at least one calibrant ion and each calibrant ion in the first set of calibrant ions has a known mass-to-charge ratio; e) transmitting the filtered first analyte and the first set of calibrant ions from the ion trap for detection; f) detecting the filtered first analyte to generate a first analyte mass signal peak representing the filtered first analyte, and detecting each calibrant ion in the first set of calibrant ions to generate an associated calibrant mass signal peak for each calibrant ion in the first set of calibrant ions; and, g) calibrating a first mass signal derived from the first analyte mass signal peak by comparing the known mass-to-charge ratio and the associated calibrant mass signal peak for each calibrant ion in the first set of calibrant ions.