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US 6,140,638 AGranted
Bandpass reactive collision cell
AssigneeMDS Inc.
InventorsScott D. Tanner, Vladimir I. Baranov
Life of this patent
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AssigneeMDS Inc.
InventorsScott D. Tanner, Vladimir I. Baranov
Estimating the term…
A method of reducing isobaric interferences by transmitting ions from an ion source through an ion transmission device, typically a quadrupole collision cell, and then into an analyzing mass spectrometer, in which the collision cell is operated with a pass band which rejects intermediate ions which would otherwise tend to react to form isobaric interferences. Preferably ammonia is used as a reaction gas in the collision cell. Depending on the chemistry involved, the collision cell may be operated to set the low mass cutoff at an appropriate level, or more usually, the pass band will have both high and low mass cutoffs determined by applying both RF and DC to the collision cell. The collision cell may also be operated with a pass band to transmit ions into a time-of-flight (TOF) mass spectrometer, thus limiting the mass range of ions entering the TOF and thereby improving the duty cycle of the TOF.
A method of operating a mass spectrometer system including an ion transmission device, the method comprising:
A mass spectrometer system comprising:
A method of operating a mass spectrometer system in which ions are transmitted through a collision cell and into an analyzing mass spectrometer, said method comprising supplying ammonia to said collision cell as a collision gas, wherein said collision cell has an entrance for receiving ions, and wherein said ammonia is injected into said entrance end.
A method of operating a mass spectrometer system in which a stream of ions is transmitted into a collision cell, said collision cell having an entrance end, said method comprising supplying a reactive collision gas into said stream of ions at a location in front of and spaced from said entrance end, thus to promote reactions between said reactive collision gas and said ions before said ions enter said collision cell.
A mass spectrometer system having an ion source for producing sample ions, an ion transmission device having an entrance for receiving said sample ions, a reaction gas supply, and a conduit for carrying said reaction gas from said reaction gas supply for said reaction gas to enter said ion transmission device, and means for applying excitation to said ion transmission device to set low and high mass cutoffs therein with a bandpass therebetween, wherein said conduit is positioned to carry said reaction gas to a location between said ion source and said entrance, said location being spaced upstream of said entrance.
A mass spectrometer system having an ion source for producing sample ions, an ion transmission device having an entrance for receiving said sample ions and an exit, and an analyzing mass spectrometer for receiving ions from said exit of said ion transmission device, a reaction gas supply, and a conduit for carrying said reaction gas from said reaction gas supply to the entrance of said ion transmission device, so that ions entering said ion transmission device will pass through said reaction gas as they travel into said ion transmission device.
A method of operating a mass spectrometer system in which sample ions are transmitted through an ion transmission device, some of said sample ions being ions which are to be selected, others of said sample ions being precursor ions which may react in said ion transmission device to cause formation of ions or metastables which may create isobaric or non-spectral interferences with said selected ions, said method comprising operating said ion transmission device to eject at least some of said precursor ions therefrom, so as to reduce said interferences, wherein said ion transmission device has an entrance for ions from a chamber having a first pressure therein and an exit for ions into a second chamber having a second pressure therein, and including the step of selectively controlling the venting of said ion transmission device into said second chamber.
A mass spectrometer system having an ion source for producing sample ions, an ion transmission device having an entrance for receiving said sample ions and an exit, and an analyzing mass spectrometer for receiving ions from said exit of said ion transmission device, a reaction gas supply, and a conduit for carrying said reaction gas from said reaction gas supply to the entrance of said ion transmission device, so that ions entering said ion transmission device will pass through said reaction gas as they travel into said ion transmission device, and including a vent at said exit end of said ion transmission device, and a mechanism for controlling the size of said vent, for selecting controlling venting at said exit end of said ion transmission device.
A method of operating a mass spectrometer system in which sample ions are transmitted through an ion transmission device, some of said sample ions being ions which are to be selected, others of said sample ions being precursor ions which may react in said ion transmission device to cause formation of ions or metastables which may create isobaric or non-spectral interferences with said selected ions, said method comprising operating said ion transmission device to eject at least some of said precursor ions therefrom, so as to reduce said interferences, wherein RF is applied to said ion transmission device, and including the step of setting the amplitude of said RF to add a selected energy to ions therein and thereby discriminating between isobaric ions having different thermochemical properties and the step of adding a reactive collision gas to said ion transmission device, said discrimination of said isobaric ions being with respect to their different thermochemical properties with respect to said reactive collision gas.
Dependencies are inferred from the claim text.