IMPROVED COLLISIONALLY ACTIVATED DISSOCIATION EFFICIENCY AND MASS RESOLUTION ON A TRIPLE QUADRUPOLE MASS-SPECTROMETER SYSTEM

Collsionally activated dissociation efficiency and fragment ion mass resolution have been characterized on a triple quadrupole mass spectrometer equipped with an enclosed collision cell which is operated at relatively high pressure, The higher pressure results in improved efficiency (and therefore improved ion transmission) and better mass resolution than has been obtained previously with collision cells operated at lower pressure, Efficiencies of 30-50%, measured as the fractions of original precursor ion in Q1 which are detected as resolved fragment ions, are typical for singly charged ions, compared with 5-10% achieved previously, Mass resolution of fragment ions is improved to the point that the isotopes from quadruply charged fragment ions can be resolved.