Patent ID: 6140638
Filing Date: 2000-10-31
Classification: H01J

Abstract:
A method of operating a mass spectrometer system including an ion transmission device, the method comprising:(i) providing a reactive gas in the ion transmission device, whereby the ion transmission device functions as a reactive collision cell;(ii) supplying a stream of sample ions to the reactive collision cell including desired ions to be selected and unwanted precursor ions which may react with the reaction gas to cause the formation of ions or metastables which may result, directly or indirectly through intermediate ions, in unwanted isobaric or non-spectral interferences;(iii) determining a range of mass-to-charge ratios of at least some of the precursor ions and intermediate ions which could result in unwanted interferences; and(iv) applying an appropriate field to the reactive collision cell to establish a bandpass within the reactive collision cell covering a continuous range of mass-to-charge ratios including that of said desired ions and excluding the determined range of mass-to-charge ratios of at least some of the precursor and intermediate ions.