Methods and apparatus for analysis of mixtures by mass spectrometry

Abstract

Apparatus for analyzing components in a mixture by the steps of introducing the mixture into the ion source of a mass spectrometer, ionizing some of the individual molecules representative of the mixture, using the mass spectrometer to select a beam of ions of a single ion mass which may be characteristic of a target compound in the mixture, passing the resultant single-mass beam of ions through a gas-filled collision chamber, and then, using a second mass spectrometer, determining the mass spectrum of the collision fragment ions to confirm the identity of the target compound, and by measuring the intensity of all or part of the mass spectrum, determine its concentration or amount in the original sample mixture. The same apparatus is suitable for fundamental measurements of the collision processes, which in addition to fragmentation include ion molecule reactions, charge changing collisions, and others, in addition to analytical applications. The collision region simultaneously provides collision gas confinement, primary and fragment ion confinement, variability of collision energy, and variability of drift field in the collision chamber. It is composed of a leaky dielectric material, in the form of a cylindrical tube joining the exit of the first quadrupole mass spectrometer to the entrance of the second mass spectrometer. Methods of data collection and handling are also disclosed.