METHOD OF ANALYZING IONS IN AN APPARATUS INCLUDING A TIME OF FLIGHT MASS SPECTROMETER AND A LINEAR ION TRAP

摘要

A method of analyzing ions is carried out in a mass spectrometer apparatus comprising an ion source, a linear RF quadrupole and a time of flight mass spectrometer. Ions are generated from the ion source and passed into the linear RF quadrupole. To retain ions within the linear RF quadrupole, potentials are applied to either end of it and it is then operated as an ion trap. Ions of interest are selected in the linear RF quadrupole and unwanted ions are caused to be ejected. Selected ions are then excited and caused to collide with a neutral gas, to cause collision induced dissociation thereof, thereby forming fragment ions for analysis in the time of flight mass spectrometer. The potential of one end of the linear RF quadrupole is then adjusted to pass selected and fragment ions through to the time of flight mass spectrometer. This enables a spectrum of the selected and the fragment ions to be obtained from the time of flight mass spectrometer.