A mass spectrometer system having an ion trap and a downstream mass spectrometer is provided. A plurality of groups of ions are provided to the ion trap and a first mass-to-charge ratio is selected. The downstream mass spectrometer is configured to filter out one of (i) ions having a first unselected...http://www.google.com/patents/US7579585?utm_source=gb-gplus-sharePatent US7579585 - Method and apparatus for scanning an ion trap mass spectrometer
