Patents by Inventor John Fjeldsted
John Fjeldsted has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9482642Abstract: The collision cross section (CCS) of a sample ion may be calculated by measuring a total drift time taken by the sample ion to travel through an ion mobility spectrometry drift cell to an ion detector. The CCS may be calculated based on the total drift time measured, and on a proportionality coefficient that defines the time taken by the sample ion to travel through a mobility dominated region between the drift cell and the detector. The proportionality coefficient may be determined from measuring the total drift times of reference ions. Calculation of the CCS of the sample ion may also be based on a proportionality coefficient that defines the time taken by the sample ion to travel through a mobility-independent region where the velocity of the ion depends on the electrostatic field strength, mass and the charge state of the ion.Type: GrantFiled: January 31, 2014Date of Patent: November 1, 2016Assignee: Agilent Technologies, Inc.Inventors: Alexander Mordehai, Ruwan T. Kurulugama, Christian Klein, John Fjeldsted
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Publication number: 20150219598Abstract: The collision cross section (CCS) of a sample ion may be calculated by measuring a total drift time taken by the sample ion to travel through an ion mobility spectrometry drift cell to an ion detector. The CCS may be calculated based on the total drift time measured, and on a proportionality coefficient that defines the time taken by the sample ion to travel through a mobility dominated region between the drift cell and the detector. The proportionality coefficient may be determined from measuring the total drift times of reference ions. Calculation of the CCS of the sample ion may also be based on a proportionality coefficient that defines the time taken by the sample ion to travel through a mobility-independent region where the velocity of the ion depends on the electrostatic field strength, mass and the charge state of the ion.Type: ApplicationFiled: January 31, 2014Publication date: August 6, 2015Applicant: Agilent Technologies, Inc.Inventors: Alexander Mordehai, Ruwan T. Kurulugama, Christian Klein, John Fjeldsted
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Publication number: 20110210240Abstract: A mass spectrum is generated by a process in which, from a mass scan signal comprising original samples defining a peak, a subset of the original samples defining the peak is selected. One or more synthesized samples are synthesized from the subset of the original samples. The one or more synthesized samples provide a temporal resolution greater than the temporal resolution of the original samples. The one or more synthesized samples are summed with respective temporally-aligned accumulated samples to produce the mass spectrum. The accumulated samples are obtained from mass scan signals generated during respective previously-performed mass scan operations.Type: ApplicationFiled: December 7, 2010Publication date: September 1, 2011Inventors: August Hidalgo, John Fjeldsted, William Frazer
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Patent number: 7863556Abstract: A mass spectrum is generated by a process in which, from a mass scan signal comprising original samples defining a peak, a subset of the original samples defining the peak is selected. One or more synthesized samples are synthesized from the subset of the original samples. The one or more synthesized samples provide a temporal resolution greater than the temporal resolution of the original samples. The one or more synthesized samples are summed with respective temporally-aligned accumulated samples to produce the mass spectrum. The accumulated samples are obtained from mass scan signals generated during respective previously-performed mass scan operations.Type: GrantFiled: September 30, 2008Date of Patent: January 4, 2011Assignee: Agilent Technologies, Inc.Inventors: August Hidalgo, John Fjeldsted, William Frazer
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Publication number: 20090020697Abstract: A mass spectrum is generated by a process in which, from a mass scan signal comprising original samples defining a peak, a subset of the original samples defining the peak is selected. One or more synthesized samples are synthesized from the subset of the original samples. The one or more synthesized samples provide a temporal resolution greater than the temporal resolution of the original samples. The one or more synthesized samples are summed with respective temporally-aligned accumulated samples to produce the mass spectrum. The accumulated samples are obtained from mass scan signals generated during respective previously-performed mass scan operations.Type: ApplicationFiled: September 30, 2008Publication date: January 22, 2009Inventors: August Hidalgo, John Fjeldsted, William Frazer
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Patent number: 7385185Abstract: In a tandem mass spectrometer means are provided for molecular activation of ions prior to fragmentation. An embodiment of a tandem mass spectrometer comprises a first collision cell receiving analyte ions having an internal energy and a second collision cell situated downstream from the first collision cell wherein the first collision cell increases the internal energy of the analyte ions prior to entry of the ions into the second collision cell, the increase in internal energy imparted in the first collision cell alone being insufficient to fragment a substantial portion of the analyte ions. Another embodiment includes a collision cell with a heating device situated adjacent to the collision cell for controlling the temperature within the collision cell.Type: GrantFiled: December 20, 2005Date of Patent: June 10, 2008Assignee: Agilent Technologies, Inc.Inventors: Jerry T. Dowell, John Fjeldsted
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Publication number: 20070268171Abstract: A mass spectrometer comprises an ion detector, a first amplifier, a second amplifier, and a spectra combiner. The ion detector is configured to generate an analog signal indicative of ions detected by the ion detector. The first amplifier is configured to amplify the analog signal to provide a first amplified signal having a first gain relative to the analog signal. The second amplifier is configured to amplify the analog signal to provide a second amplified signal having a second gain relative to the analog signal, and the first gain is different than the second gain. The spectra combiner is configured to combine first summed digital samples of the first amplified signal with second summed digital samples of the second amplified signal.Type: ApplicationFiled: April 27, 2006Publication date: November 22, 2007Inventors: August Hidalgo, John Fjeldsted, William Frazer, Carl Myerholtz
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Publication number: 20070255532Abstract: A mass spectrometer comprises an ion detector, an analog-to-digital (A/D) converter, a sample adjuster, and an adder. The A/D converter is configured to receive and sample an analog signal from the ion detector thereby providing a plurality of samples. The adder is configured to sum the samples, and the summed samples define a mass spectrum. The sample adjuster is configured to identify a peak defined by the samples and to suppress at least one of the samples of the peak such that a resolution of a peak within the mass spectrum is enhanced.Type: ApplicationFiled: April 27, 2006Publication date: November 1, 2007Inventors: John Fjeldsted, August Hidalgo, William Frazer
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Publication number: 20070138383Abstract: In a tandem mass spectrometer means are provided for molecular activation of ions prior to fragmentation. An embodiment of a tandem mass spectrometer comprises a first collision cell receiving analyte ions having an internal energy and a second collision cell situated downstream from the first collision cell wherein the first collision cell increases the internal energy of the analyte ions prior to entry of the ions into the second collision cell, the increase in internal energy imparted in the first collision cell alone being insufficient to fragment a substantial portion of the analyte ions. Another embodiment includes a collision cell with a heating device situated adjacent to the collision cell for controlling the temperature within the collision cell.Type: ApplicationFiled: December 20, 2005Publication date: June 21, 2007Inventors: Jerry Dowell, John Fjeldsted
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Patent number: 5903003Abstract: The invention referres to analytic methods, the accuracy of which is increased by relating signals of analyte ions to those of reference ions, or by relating ion signals from measuring methods under special conditions to those of reference methods. If such "comparative" analysis procedures are performed in ion trap mass spectrometers, problems arise with the low dynamic measuring range covered by one spectrum in such mass spectrometers and, if different spectra are compared, with the control of the space charge within the ion trap. The invention consists in acquiring analyte spectra and reference spectra in different acquisition procedures, alternating between both types of spectrum acquisitions as fast as possible, whereby control of the space charge in the ion trap proceeds separately for the spectra of both types, the control being related to previously acquired spectra of the same type.Type: GrantFiled: February 27, 1998Date of Patent: May 11, 1999Assignee: Bruker Daltonik GmbHInventors: Michael Schubert, John Fjeldsted, Jochen Franzen
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Patent number: 4885500Abstract: A quartz quadrupole comprises a quartz substrate, conductive strips and low-conductivity strips. The substrate includes hyperbolic inner surfaces which provide the geometry for the conformed conductive strips to produce an appropriate electric field for mass filter operation. The use of quartz as a substrate material provides the thermal and electrical characteristics required by high performance mass filtering operations, including scanning mode operation to 800 amu and above. During such operation, potential field distortions by accumulated charge in cusp sections of the substrate are minimized by the low-conductivity strips, which are arranged to overlap longitudinal edges of the conductive strips. Formation of the quartz substrate is made possible by high precision machining, grinding and polishing of a refractory metal mandrel. The actual step of forming the substrate is simplified by the low thermal coefficient of expansion of the quartz.Type: GrantFiled: March 28, 1988Date of Patent: December 5, 1989Assignee: Hewlett-Packard CompanyInventors: Stuart Hansen, John Fjeldsted, Carolyn Broadbent