US 2003/0111595 A1 · Mass spectrometer

Abstract

A mass spectrometer is disclosed comprising a mass selective ion trap such as a 3D quadrupole field ion trap upstream of a pusher electrode of an orthogonal acceleration Time of Flight mass analyser. According to a first embodiment bunches of ions are released from the ion trap and the pusher electrode is energised after a delay time which is progressively varied. According to a second embodiment ions are released from the ion trap in reverse order of mass to charge ratio with the ions having the largest mass to charge ratio being released first. By appropriate release of the ions from the ion trap it is possible to ensure that substantially all of the ions arrive at the pusher electrode at substantially the same time. According to both embodiments it is possible to achieve a duty cycle approaching 100% across a large range of mass to charge ratios.

Claims58

Dependent claims

A mass spectrometer comprising:

a mass selective ion trap;
an orthogonal acceleration Time of Flight mass analyser arranged downstream of said ion trap, said orthogonal acceleration Time of Flight mass analyser comprising an electrode for orthogonally accelerating ions;
and
a control means for controlling said mass selective ion trap and said orthogonal acceleration Time of Flight mass analyser, wherein in a mode of operation said control means controls said ion trap and said orthogonal acceleration Time of Flight mass analyser so that:
(i) at a first time t1 ions having mass to charge ratios within a first range are arranged to be substantially passed from said ion trap to said orthogonal acceleration Time of Flight mass analyser whilst ions having mass to charge ratios outside of said first range are not substantially passed to said orthogonal acceleration Time of Flight mass analyser;
(ii) at a second later time t2 after t1 ions having mass to charge ratios within a second range are arranged to be substantially passed from said ion trap to said orthogonal acceleration Time of Flight mass analyser whilst ions having mass to charge ratios outside of said second range are not substantially passed to said orthogonal acceleration Time of Flight mass analyser;
and
(iii) at a later time tpush after t1 and t2 said electrode is arranged to orthogonally accelerate ions having mass to charge ratios within said first and second ranges.

5 more elements

Dependencies are inferred from the claim text.

Mass spectrometer

Life of this patent

Mass spectrometer

Life of this patent

Abstract

Claims58