US 4,736,101 A · Method of operating ion trap detector in MS/MS mode

Abstract

A simple and economical method of mass analyzing a sample by means of a quadrupole ion trap mass spectrometer in an MS/MS mode comprises the steps of forming ions within a trap structure, changing the RF and DC voltages in such a way that the ions with mass-to-charge ratios within a desired range will be and remain trapped within the trap structure, dissociating such ions into fragments by collisions and increasing the field intensity again so that the generated fragments will become unstable and exit the trap volume sequentially to be detected. A supplementary AC field may be applied additionally to provide various scan modes as well as dissociate the ions.

Claims14

Dependent claims

A method of mass analyzing a sample comprising the steps of

defining a trap volume with a three-dimensional quadrupole field adapted to trap ions within a predetermined range of mass-to-charge ratio,
forming or injecting ions within said trap volume such that those within said predetermined mass-to-charge range are trapped within said trap volume,
changing said quadrupole field to eliminate ions having a mass-to-charge ratio other than that of the ions of desired charge-to-mass ratio to be analyzed,
readjusting said quadrupole field to capture daughter ions of said ions of desired charge-to-mass ratio
dissociating or reacting said trapped desired ions such that those of said ions and said daughters within a desired range of mass-to-charge ratio remain trapped within said trap volume, and
then changing the quadrupole field to cause ions of consecutive mass to escape said trap volume for detection.

3 more elements

Dependencies are inferred from the claim text.

Method of operating ion trap detector in MS/MS mode

Life of this patent

Method of operating ion trap detector in MS/MS mode

Life of this patent

Abstract

Claims14