Patents by Inventor John R. Berg

John R. Berg 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).

  • Patent number: 6164144
    Abstract: An improved method and apparatus are described for carrying out SPME onto the inner surface of a syringe needle at least partially coated with a stationary phase followed by desorption of analytes from a sample into a gas chromatograph injector for analysis. The SPME apparatus comprises a syringe having a syringe barrel and a plunger slidable within one end of the barrel, a hollow needle extending from the other end of the barrel and having its inner surface coated with the stationary phase, and fluid communication means for transferring a fluid into contact with the coated inner surface of said hollow needle. During the analysis phase, a carrier gas is transferred into contact with the coated inner surface. A valve means can be used to switch the flow of sample from a container containing the sample during the microextraction phase to the carrier gas during the analysis phase.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: December 26, 2000
    Assignee: Varian, Inc.
    Inventor: John R. Berg
  • Patent number: 4999162
    Abstract: A flame detector comprising a ceramic flame jet for use in a high temperature gas chromatography system is disclosed. The interior volume of the flame jet is fabricated of a highly inert ceramic material so that sample eluting from the end of a gas chromatography column located within the interior volume of the flame jet does not contact any metallic surface en route to the flame. By avoiding sample contact with metallic surfaces, interferences which are prone to occur at high temperature, such as peak tailing, are avoided. In a further aspect the flame detector is treated with a silylating reagent to further passivate the surfaces which may affect the sample.
    Type: Grant
    Filed: August 26, 1988
    Date of Patent: March 12, 1991
    Assignee: Varian Associates, Inc.
    Inventors: Gregory J. Wells, John R. Berg