Oregon State University

State of Oregon

Max L Deinzer

Joseph S Beckman

Valery G Voinov

Douglas F Barofsky

James A Laramee

Mass spectrometry cells include one or more interleaved magnetostatic and electrostatic lenses. In some examples, the electrostatic lenses are based on electrical potentials applied to magnetostatic lens pole pieces. In other alternatives, the electrostatic lenses can include conductive apertures. Applied voltages can be selected to trap or transport charged particles, and photon sources, gas sources, ion sources, and electron sources can be provided for various dissociation processes.

Radio-frequency-free hybrid electrostatic/magnetostatic cell for transporting, trapping, and dissociating ions in mass spectrometers

Methods are disclosed for ascertaining whether molecules of a particular analyte are present in a sample. Molecules from the sample are passed into an electron monochromator in which the molecules are contacted by monochromatic electrons having a kinetic energy level within a range of greater than zero eV to less than about 6 eV. These energy levels are sufficient to form ions from at least a subpopulation of the molecules by electron capture by molecules of the subpopulation. The ions formed in the electron monochromator are then passed through a mass analyzer to obtain an ion spectrum which allows a determination to be made as to whether or not the ions profiled in the spectrum include ions produced from the analyte. Thus, the disclosed methods allow greatly enhanced detection of particular analytes of interest, such as explosives, drugs, pesticides, and other compounds of environmental, security, forensic, or other concern. The methods are particularly suitable for mass analysis of anions produced by electron capture of monochromatic electrons by certain molecules entering the electron monochromator. Improvement in detection sensitivity over conventional methods is about three orders of magnitude or more with substantially improved resolution. Use of a molecule-separating device, such a gas chromatograph, upstream of the electron monochromator can provide further improvement over conventional methods.

Methods for analyzing a sample for a compound of interest using mass

Methods and apparatuses are disclosed for mass-analysis of a sample for particular analytes of interest. An electron monochromator is coupled to any of a number of different types of mass analyzer and used to generate slow electrons used to produce ions of target molecules for mass analysis. The electrons have a narrow energy bandwidth and high intensity, even at nearly zero kinetic energy levels. The median energy level of the electrons can be preset, permitting selection of specific target molecules to be ionized. Both positive and negative-ion mass analysis can be performed. Electron-capture negative-ion mass spectrometry is particularly enhanced, with a sensitivity about three orders of magnitude greater than in results obtained using conventional negative-ion equipment. Also, a buffer gas is eliminated, allowing substantial reductions in negative-ion equipment size, weight, and energy consumption. The mass analyzer can be an ion trap, making possible sensitive analysis of low concentrations of chemical analytes, such as environmental contaminants, using a hand-held instrument. Multiple mass analyzers, or combinations of a mass analyzer with other analytical instruments such a gas chromatograph, can be coupled to the electron monochromator.

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Corvallis, OR, United States of America

Max L Deinzer