Back to results
US 4,755,670 AGranted
Fourtier transform quadrupole mass spectrometer and method
AssigneeFinnigan Corporation
InventorsJohn E. P. Syka, William J. Fies, Jr.
Life of this patent
Estimating the term…
Abstract
A quadrupole mass spectrometer in which a sample to be analyzed is ionized in a two or three dimensional electrostatic trapping field, and the ions in the range of the mass-to-charge ratios to be analyzed are excited at their characteristic frequencies of motion. The excited ions generate image currents which are detected and processed to provide a mass spectrum.
Claims19
A quadrupole mass spectrometer comprising
- a quadrupole structure
- means for applying an RF voltage to said structure to form an electrostatic trapping field in said structure,
- ionizing means for ionizing a sample in said trapping field and forming sample ions with a mass range being trapped in said field,
- means for applying a pulse of energy to said trapped ions whose frequency distribution includes frequencies corresponding to characteristic frequencies of motion for the ions in the range of mass-to-charge ratios to be analyzed to cause characteristic motion of said ions, and
- means for detecting image currents induced by the characteristic motion of said ions.
2 more elements
A quadrupole mass spectrometer comprising
- a quadrupole structure including spaced end caps and a ring electrode,
- means for applying an RF voltage between the ring electrode and at least one end cap to form a three dimentional electrostatic field,
- an electron gun means for injecting ionizing electrons into said quadrupole structure to ionize a sample and form ions which are trapped in said field,
- excitation pulse means for applying an excitation pulse to at least one of said end caps to cause characteristic motion of said trapped ions, and
- detection means connected to at least one end cap for detecting the characteristic motion of ions in said quadrupole structure responsive to said excitation pulse.
2 more elements
A quadrupole mass spectrometer comprising
- a quadrupole structure including spaced linear quadrupole rods and end plates closing the end of the structure,
- means for applying an RF voltage between said quadrupole rods,
- means for applying a DC voltage between end plates wherein said RF and DC voltages form a two dimensional electrostatic field,
- an electron gun means for providing ionizing electrons into said quadrupole structure to ionize a sample and form ions which are trapped in said field,
- excitation pulse means for applying an excitation pulse to at least two quadrupole rods to cause characteristic motion of said trapped ions, and
- detection means connected to at least two of said rods for detecting the characteristic motion of ions in said quadrupole structure responsive to said excitation pulse.
3 more elements
The method of mass analyzing ions trapped in a quadrupole spectrometer structure which comprises the steps of
- applying an RF voltage to the quadrupole structure to form an electrostatic trapping field,
- ionizing a sample in said trapping field wherein ions over a range of mass-to-charge ratios are trapped,
- applying an excitation voltage to said quadrupole structure, said excitation voltage including frequencies corresponding to characteristic frequencies of motion of trapped ions in the range of mass-to-charge ratios to be analyzed,
- detecting, after the excitation voltage has terminated, ion image current induced by characteristic ion motion, and
- amplifying and recording induced ion currents signals.
2 more elements
The method of mass analyzing ions trapped in a quadrupole spectrometer structure which comprises the steps of
- applying an RF voltage to the quadrupole structure to form an electrostatic trapping field,
- ionizing a sample in said trapping field wherein ions over a range of mass-to-charge ratios are trapped,
- expelling ions of unwanted mass from said trapping field,
- applying a voltage to said structure which causes the ions to undergo collisionally induced dissociation,
- applying an excitation voltage to said quadrupole structure, said excitation voltage including frequencies corresponding to characteristic frequencies of motion of dissociated trapped ions in the range of mass-to-charge ratios to be analyzed,
- detecting, after the excitation voltage has terminated, ion image current induced by characteristic ion motion, and
- amplifying and recording induced ion currents signals.
4 more elements
Dependencies are inferred from the claim text.