Patents Represented by Attorney Burke M. Hallderson
  • Patent number: 5433838
    Abstract: Improved capillary electrophoresis apparatus of the type that generally includes a capillary tube, the capillary tube having a sample inlet end and an outlet end, a first electrode in electrical communication with the inlet end of the capillary tube, a second electrode in electrical communication with the outlet end of the capillary tube and a high voltage power supply in electrical communication with the first and second electrodes. The improvement is to connect a miniature Ion Chromatography membrane suppressor to the outlet end of the capillary tube, to connect a conductivity detector to the membrane suppressor and to place the second electrode in the regenerant compartment of the membrane suppressor.
    Type: Grant
    Filed: June 10, 1994
    Date of Patent: July 18, 1995
    Assignee: The Dow Chemical Company
    Inventors: Purnendu Dasgupta, Bao Li-Yuan
  • Patent number: 5242471
    Abstract: Apparatus and methods are provided for using a detector designed for use with liquids to detect resolved analytes in an effluent stream from a gas chromatography instrument. The gaseous stream is entrained by a flowing liquid solvent, and at least a portion of the analytes are transferred from the gas phase to the liquid phase. The liquid solvent containing the analytes is then conveyed to a detector designed for liquid analysis. Thus, the present invention gives the analyst more options for detecting an analyte or a group of analytes, thereby providing greater flexibility in optimizing the sensitivity or selectivity of the analysis. Furthermore, the present invention allows gaseous effluents to be analyzed by detectors which more readily permit sample recovery than the detectors currently being used to analyze gaseous effluents.
    Type: Grant
    Filed: May 22, 1992
    Date of Patent: September 7, 1993
    Assignee: The Dow Chemical Company
    Inventors: Dan A. Markham, Patrick W. Langvardt