Patents by Inventor James D. Luedtke

James D. Luedtke 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).

  • Solid phase extraction medium
    Patent number: 5279742
    Abstract: A method for isolating an environmentally hazardous organic contaminant from a fluid utilizes a solid phase extraction medium comprises a PTFE fibril matrix, and sorptive particles enmeshed in said matrix comprising more than 30 and up to 100 weight percent of porous organic particles, and less than 70 to 0 weight percent of porous (organic-coated or uncoated) inorganic particles, the ratio of sorptive particles to PTFE being in the range of 40:1 to 1:4 by weight. The extraction medium is useful in pesticide, phenolics, and residue of explosives separations. The separations can be efficiently performed in a stacked disk format.
    Type: Grant
    Filed: August 14, 1992
    Date of Patent: January 18, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Craig G. Markell, Donald F. Hagen, James D. Luedtke
  • Solid phase extraction medium
    Patent number: RE36811
    Abstract: A method for isolating an environmentally hazardous organic contaminant from a fluid utilizes a solid phase extraction medium comprises a PTFE fibril matrix, and sorptive particles enmeshed in said matrix comprising more than 30 and up to 100 weight percent of porous organic particles, and less than 70 to 0 weight percent of porous (organic-coated or uncoated) inorganic particles, the ratio of sorptive particles to PTFE being in the range of 40:1 to 1:4 by weight. The extraction medium is useful in pesticide, phenolics, and residue of explosives separations. The separations can be efficiently performed in a stacked disk format.
    Type: Grant
    Filed: October 24, 1994
    Date of Patent: August 8, 2000
    Assignee: Minnesota Mining and Manufacturing Co.
    Inventors: Craig G. Markell, Donald F. Hagen, James D. Luedtke