摘要:
A mass spectrometer is disclosed comprising a MALDI ion source coupled to an orthogonal acceleration Time of Flight mass analyser (13). The mass spectrometer is operated at a first instrument setting wherein specific parent ions are selected by a mass filter and are accelerated to a first axial energy. The fragment ions are then orthogonally accelerated after a first delay time and first mass spectral data is obtained. The mass spectrometer is then operated at a second instrument setting wherein the axial energy of the parent ions is increased and the resulting fragment ions are orthogonally accelerated after a reduced delay time. Second mass spectral data is then obtained. The first and second mass spectral data are then combined to provided a final composite mass spectrum.
摘要:
A mass spectrometer is disclosed wherein highly charged fragment ions resulting from Electron Transfer Dissociation fragmentation of parent ions are reduced in charge state within a Proton Transfer Reaction cell 35 by reacting the fragment ions with a neutral superbase reagent gas such as Octahydropyrimidolazepine.
摘要:
A mass spectrometer is disclosed comprising a glow discharge device within the initial vacuum chamber of the mass spectrometer. The glow discharge device may comprise a tubular electrode (14) located within an isolation valve (15) which is provided in the vacuum chamber. Reagent vapour may be provided through the tubular electrode (14) which is then subsequently ionised by the glow discharge. The resulting reagent ions may be used for Electron Transfer Dissociation of analyte ions generated by an atmospheric pressure ion source. Other embodiments are contemplated wherein the ions generated by the glow discharge device may be used to reduce the charge state of analyte ions by Proton Transfer Reaction or may act as lock mass or reference ions.
摘要:
A mass spectrometer is disclosed comprising a MALDI ion source coupled to an orthogonal acceleration Time of Flight mass analyser (13). The mass spectrometer is operated at a first instrument setting wherein specific parent ions are selected by a mass filter and are accelerated to a first axial energy. The fragment ions are then orthogonally accelerated after a first delay time and first mass spectral data is obtained. The mass spectrometer is then operated at a second instrument setting wherein the axial energy of the parent ions is increased and the resulting fragment ions are orthogonally accelerated after a reduced delay time. Second mass spectral data is then obtained. The first and second mass spectral data are then combined to provided a final composite mass spectrum.
摘要:
A mass spectrometer is disclosed comprising an Electron Transfer Dissociation device comprising an ion guide. A control system determines the degree of fragmentation and charge reduction of precursor ions within the ion guide and varies the speed at which ions are transmitted through the ion guide in order to optimise the fragmentation and charge reduction process.
摘要:
A mass spectrometer is disclosed comprising a mass selective ion trap or mass analyser (4) arranged upstream of an ion guide (6). Ions are scanned out of the mass selective ion trap or mass analyser (4) and are received in one or more axial potential wells created or formed within the ion guide (6). One or more transient DC voltages or potentials are preferably applied to the ion guide (6) in order to create a plurality of axial potential wells which are translated along the length of the ion guide (6). Ions are released in packets from the exit of the ion guide (6) and are orthogonally accelerated into a drift or flight region of an orthogonal acceleration Time of Flight mass analyser (13) with a relatively high duty cycle.