Abstract: A time-of-flight mass spectrometer for measuring the mass-to-charge ratio of a sample molecule is described. The spectrometer provides independent control of the electric field experienced by the sample before and during ion extraction. Methods of mass spectrometry utilizing the principles of this invention reduce matrix background, induce fast fragmentation, and control the transfer of energy prior to ion extraction.

Abstract: A time-of-flight mass spectrometer for measuring the mass-to-charge ratio of a sample molecule is described. The spectrometer provides independent control of the electric field experienced by the sample before and during ion extraction. Methods of mass spectrometry utilizing the principles of this invention reduce matrix background, induce fast fragmentation, and control the transfer of energy prior to ion extraction.

Abstract: A time-of-flight mass spectrometer for measuring the mass-to-charge ratio of a sample molecule is described. The spectrometer provides independent control of the electric field experienced by the sample before and during ion extraction. Methods of mass spectrometry utilizing the principles of this invention reduce matrix background, induce fast fragmentation, and control the transfer of energy prior to ion extraction.

Abstract: A time-of-flight mass spectrometer for measuring the mass-to-charge ratio of a sample molecule is described. The spectrometer provides independent control of the electric field experienced by the sample before and during ion extraction. Methods of mass spectrometry utilizing the principles of the invention reduce matrix background, induce fast fragmentation, and control the transfer of energy prior to ion extraction.

Abstract: The system for analyzing multiple samples includes a plurality of portable of sample supports each for accommodating a plurality of samples thereon, and an identification mechanism for identifying each sample location on each of the plurality of sample supports. The mass spectrometer is provided for analyzing each of the plurality of samples when positioned within a sample receiving chamber, and a laser source strikes each sample with a laser pulse to desorb and ionize sample molecules. The support transport mechanism provided for automatically inputting and outputting each of the sample supports from the sample receiving chamber of the mass spectrometer. A vacuum lock chamber receives the sample supports and maintains at least one of the sample supports within a controlled environment while samples on another of the plurality of sample supports are being struck with laser pulses. The computer is provided for recording test data from the mass spectrometer and for controlling the operation of the system.

Abstract: A time-of-flight mass spectrometry and method of operating a TOF mass spectrometer are disclosed. The mass spectrometer includes one or more electrically charged accelerating plates for accelerating ions, a reflector, a first ion drift region upstream from the reflector, a second ion drift region downstream from the deflector, and an ion detector. The ion reflector includes a primary reflecting field for decelerating ions and reflecting low energy ions, and a second reflecting field for reflecting high energy ions and for establishing a substantially uniform ion flight time through the one or more accelerating fields and reflecting fields. According to the method of the present invention, the length of the ion drift regions may be adjusted such that ion travel time through these regions is equal to the ion travel time through the accelerating and reflecting fields.

Abstract: Improved techniques are provided for forming ionized molecules from electrosprayed droplets for analysis by a mass spectrometer. A high voltage is applied to a capillary tube for spraying droplets at substantially atmospheric pressure or above, and the electrosprayed droplets contain sample solute of interest and solvent. The electrosprayed droplets are passed into an ion generating chamber which is maintained at a pressure in the range of from 0.1 Torr to 10 Torr. The walls of the ion generating chamber are controllably heated to a temperature which will desolvate the droplets and produce ionized molecules of interest for analysis by the mass spectrometer. The electrospray technique does not rely upon a countercurrent heated gas flow, and provides a particularly simple and inexpensive means to couple electrospray ionization to either quadrupole or magnetic mass analyzers.

Abstract: This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, identification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photometry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution.

Abstract: An improved interface is provided for receiving effluent from a chromatographic device and outputting sample particles of interest to a detector for analysis. The interface includes a gas diffusion cell having a membrane therein separating the cell into an aerosol flow chamber and a sweep gas flow chamber. The effluent is sprayed as an aerosol into the aerosol flow chamber, and vaporized solvent diffuses through the gas membrane into the sweep gas flow chamber while particles of interest are output to the detector. Sweep gas is passed through the sweep gas flow chamber for removing the solvent vapor, and the flow rate of sweep gas is controlled to achieve little or no net flow of gas across the membrane. Efficient solvent removal may be achieved at room temperature for certain LC flow rates, and high detector resolution is possible by maintaining laminar flow of the carrier gas through the aerosol flow chamber.

Abstract: An improved thermospray vaporizer is provided for obtaining an ion vapor from a liquid sample separated by chromatography for detection or analysis by a mass spectrometer. A thermospray vaporizer comprises a capillary tube for receiving the sample, and having a jet nozzle at one end removably affixed to the capillary tube with an aperture selectively sized for a range of sample flow rates and compositions. The jet nozzle includes a generally planar sapphire insert having a cylindrical-shaped aperture of a preselected diameter. The sapphire insert is swaged into a bass holder which has a slightly larger diameter aperture than the insert. A ferrule seals between the capillary tube and an end fitting, which is welded at one end to the outer sheath of the thermospray probe and retains and end nut at the other end to secure the holder in place. The insert is thus easily replaced by removing the end nut and the brass holder with the insert.

Abstract: Improved techniques are provided for interfacing liquid chromatography with gas phase and solid phase detectors. Heated liquid effluent including sample solute of interest and solvent is sprayed into a desolvation chamber, where controlled vaporization of the solvent occurs while maintaining sample particles of interest. A carrier gas is added to the desolvation chamber, and the discharged aerosol is transmitted through a uniform cross-sectional flow path to a condenser, gas diffusion cell, or other solvent removal device. Substantially all transmitted solvent is thereby removed, with the carrier gas and substantially all of the sample particles of interest passing to the detector for analysis. The interface of the present invention is applicable to thermospray technology and other spraying techniques resulting in vaporization and nebulization of the LC effluent.

Abstract: This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, indentification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photometry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution.

Abstract: This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, identification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photometry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution.

Abstract: Improved methods and apparatus are disclosed for detecting negative ions and, more particularly, for detecting negative ions produced from a quadrupole mass spectrometer. By modulating the ion beam either at the ion source or within the ion focusing system, the output current from the electron multiplier detector is a pulsating current which is then capacitively or inductively coupled from a high direct current potential to ground level. Electronics operating at ground level are employed to correct the current signal distortion due to the capacitive or inductive coupling of the detector output current. The present invention enables substantially increased detector sensitivity to negative ions compared to prior art equipment, and does not require expensive and complex preamplifier circuitry. The techniques of the present invention allow both positive and negative ions to be detected utilizing the same basic equipment, thereby increasing equipment versatility and reducing costs.

Abstract: Improved methods and apparatus suitable for use in mass spectrometry are provided for dissociating ions by achieving electronic excitation of the ions using electrons. In MS-MS applications, ion dissociation is induced by electron impact on an ion beam after the beam has exited a first mass analyzer, and before the beam enters a second analyzer. An efficient method for dissociating ions is achieved by providing a low velocity ion beam traveling substantially along the axis of an RF excited multipole field, and intersecting sheet electron beams traveling transverse to the axis of the field. When used in the analysis of high molecular weight, nonvolatile molecules, the teachings of the present invention yield the extensive and reproducible fragmentation characteristics generally associated with electron ionization of lower mass, volatile molecules.

Abstract: This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, indentification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photemetry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution.