Harald Oser

US Patent:

7095016, Aug 22, 2006

Filed:

Apr 29, 2004

Appl. No.:

10/836644

Inventors:

Harald Oser - Menlo Park CA, US
Michael J. Coggiola - Sunnyvale CA, US
Steven E. Young - Mountain View CA, US
David R. Crosley - Palo Alto CA, US

Assignee:

SRI International - Menlo Park CA

International Classification:

H01J 49/04

US Classification:

250288, 250289

Abstract:

A method and apparatus are provided for analyzing an analyte at low concentration in a liquid sample by photoionization and mass spectrometry. An inlet system is provided for direct injection of the liquid sample using a capillary tube. The method and apparatus allow for 20 to 2000-fold improvement of the lower detection limit of an analyte in a liquid sample compared to a conventional liquid chromatography/mass spectrometer apparatus.

US Patent:

7161145, Jan 9, 2007

Filed:

Apr 20, 2005

Appl. No.:

11/111491

Inventors:

Harald Oser - Menlo Park CA, US
Michael J. Coggiola - Sunnyvale CA, US
Steven E. Young - Mountain View CA, US
Grace F. Chou - Mountain View CA, US

Assignee:

SRI International - Menlo Park CA

International Classification:

H01J 49/10

US Classification:

250288, 250282, 250423 P

Abstract:

A method and apparatus are provided for identifying analytes at low concentrations in a liquid sample. The liquid sample is introduced through a continuous flow membrane inlet system. The analytes that permeate the membrane are analyzed by photoionization-time-of-flight mass spectrometry. The analytes remaining in the liquid sample that do not permeate the membrane are conducted to a capillary tube inlet that introduces the liquid sample and other analytes as droplets into the photoionization zone. Any analytes remaining absorbed or adsorbed on the membrane are driven through the membrane by application of heat. Analytes may be analyzed by either resonance enhanced multiphoton ionization (REMPI) or single photon ionization (SPI), both of which are provided in the apparatus and can be selected as alternative sources.

US Patent:

20200227244, Jul 16, 2020

Filed:

Mar 26, 2020

Appl. No.:

16/831685

Inventors:

- San Jose CA, US
Harald OSER - San Carlos CA, US

International Classification:

H01J 49/00
H01J 49/42

Abstract:

A mass spectrometer includes a collision cell and a system controller. The collision cell includes a plurality of rod pairs configured to generate pseudopotential well through the application of radio frequency potentials to the rod pairs. The collision cell configured to generate a target fragment from a parent ion by colliding the parent ion with one or more gas molecules. The system controller is configured to set a radio frequency amplitude of the radio frequency potentials to a default amplitude; monitor the production of a target fragment ion while adjusting the collision energy; set the collision energy to optimize the production of the target fragment ion; apply a linear full range ramp to the radio frequency amplitude to determine an optimal radio frequency amplitude; and set the radio frequency amplitude to the optimal radio frequency amplitude for the parent ion, target fragment ion pair.

US Patent:

20200194244, Jun 18, 2020

Filed:

Dec 14, 2018

Appl. No.:

16/220928

Inventors:

- San Jose CA, US
Harald OSER - San Carlos CA, US

International Classification:

H01J 49/00
H01J 49/06
H01J 49/42

Abstract:

A multipole ion guide includes a plurality of electrodes disposed about a longitudinal axis of the device so as to define an ion transmission volume for transmitting ions along a length of the device between opposite inlet and outlet ends. An electronic controller is operably connected to an RF power source and to at least some of the electrodes and is configured to apply at least an RF potential to the electrodes. During use the electrodes generate an RF-only field along a first portion of the device and an axial DC field along a second portion of the device. Ions are focused radially inward toward the longitudinal axis of the device by the RF-only field within the first portion of the device prior to and/or subsequent to experiencing the axial DC field within the second portion of the device.

US Patent:

20190074168, Mar 7, 2019

Filed:

Nov 5, 2018

Appl. No.:

16/181280

Inventors:

- San Jose CA, US
Harald OSER - San Jose CA, US

International Classification:

H01J 49/00
H01J 49/42

Abstract:

A mass spectrometer includes a collision cell and a system controller. The collision cell includes a plurality of rod pairs configured to generate pseudopotential well through the application of radio frequency potentials to the rod pairs. The collision cell configured to generate a target fragment from a parent ion by colliding the parent ion with one or more gas molecules. The system controller is configured to set a radio frequency amplitude of the radio frequency potentials to a default amplitude; monitor the production of a target fragment ion while adjusting the collision energy; set the collision energy to optimize the production of the target fragment ion; apply a linear full range ramp to the radio frequency amplitude to determine an optimal radio frequency amplitude; and set the radio frequency amplitude to the optimal radio frequency amplitude for the parent ion, target fragment ion pair.

US Patent:

20180254174, Sep 6, 2018

Filed:

Mar 1, 2017

Appl. No.:

15/446756

Inventors:

- San Jose CA, US
Harald OSER - San Jose CA, US

International Classification:

H01J 49/00
H01J 49/42

Abstract:

A mass spectrometer includes a collision cell and a system controller. The collision cell includes a plurality of rod pairs configured to generate pseudopotential well through the application of radio frequency potentials to the rod pairs. The collision cell configured to generate a target fragment from a parent ion by colliding the parent ion with one or more gas molecules. The system controller is configured to set a radio frequency amplitude of the radio frequency potentials to a default amplitude; monitor the production of a target fragment ion while adjusting the collision energy; set the collision energy to optimize the production of the target fragment ion; apply a linear full range ramp to the radio frequency amplitude to determine an optimal radio frequency amplitude; and set the radio frequency amplitude to the optimal radio frequency amplitude for the parent ion, target fragment ion pair.

US Patent:

20180102239, Apr 12, 2018

Filed:

Dec 8, 2017

Appl. No.:

15/836101

Inventors:

- San Jose CA, US
Harald OSER - San Carlos CA, US

International Classification:

H01J 49/00
H01J 49/42

Abstract:

A mass spectrometer system comprises: (a) an ion source; (b) a mass filter; (c) a mass analyzer; (d) a partitioned ion fragmentation cell configured to receive ions from the mass filter and to outlet fragment ions to the mass analyzer comprising: (d1) a set of multipole rod electrodes; a housing enclosing the set of multipole rod electrodes and comprising an ion inlet and an ion outlet; (d2) a set of partitions within the housing separating the housing interior into a plurality of compartments; and (d3) a plurality of gas inlets, each gas inlet fluidically coupled to a source of a collision gas and to a respective compartment and having a respective inlet shutoff valve; and (e) a controller electrically coupled to each inlet shutoff valve and configured to independently control the pressure of collision gas within each compartment.

US Patent:

20170162371, Jun 8, 2017

Filed:

Dec 8, 2015

Appl. No.:

14/963123

Inventors:

- San Jose CA, US
Harald OSER - San Carlos CA, US

International Classification:

H01J 49/00
H01J 49/42

Abstract:

A method for operating a mass spectrometer so as to detect or quantify analytes, comprises: (a) identifying a selected-reaction-monitoring (SRM) transition to be used for each respective analyte; (b) determining a time duration required for a fragmentation reaction corresponding to each identified transition to proceed to a threshold percentage of completion; and (c) for each analyte, performing the steps of (i) isolating ions corresponding to a precursor-ion mass-to-charge (m/z) ratio of the respective transition; (ii) fragmenting the respective isolated ions in one of two fragmentation cells or fragmentation cell portions; and (ii) mass analyzing for fragment ions corresponding to a product-ion m/z ratio of the respective transition, wherein, for each analyte, the fragmentation cell or fragmentation cell portion that is used for fragmenting the isolated ions is determined from the time duration determined for the respective analyte.