Patent ID: 8633435
Filing Date: 2014-01-21
Classification: H01J

Abstract:
1. A mass spectrometer comprising: a collision, fragmentation or reaction device, said collision, fragmentation or reaction device having an entrance aperture, an exit aperture, and electrodes, located between the entrance aperture and the exit aperture, said electrodes including apertures through which ions are transmitted in use, the apertures being substantially the same size, the electrodes including at least a first section comprising a first group of the electrodes and a second separate section comprising a second separate group of the electrodes, wherein the electrodes form a single ion guide constituted by the first and second sections; a first device for applying or supplying a first AC or RF voltage having a first frequency and a first amplitude to said first group of electrodes so that, in use, parent or precursor ions having a first mass to charge ratio experience a first radial pseudo-potential electric field or force having a first strength or magnitude which acts to confine the parent or precursor ions radially within said first group of the electrodes or said first section; and a second device for applying or supplying a second AC or RF voltage, which is different from the first AC or RF voltage, having a second frequency and a second amplitude to said second group of the electrodes so that, in use, fragment ions formed from the parent or precursor ions having said first mass to charge ratio experience a second radial pseudo-potential electric field or force having a second strength or magnitude which acts to confine the fragment ions radially within said second group of the electrodes or said first section, wherein said second strength or magnitude is different to said first strength or magnitude.