The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1993
Filed:
Apr. 15, 1992
Joseph F Hiller, Midland, MI (US);
Glen H Hughes, Midland, MI (US);
Daniel P Martin, Midland, MI (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
Apparatus and method for temperature gradient capillary gas chromatography wherein the chromatography column is surrounded by an inner tube and the inner tube is surrounded by an outer tube. A first heat transfer fluid is heated to a first temperature and is flowed between the inner tube and the column in the same direction as the flow of carrier gas through the capillary column. A second heat transfer fluid is heated to a second temperature and is flowed in the opposite direction between the outer tube and the inner tube, the second temperature being lower than the first temperature. The invention is also an improved capillary gas chromatography method of the type that generally includes the steps of flowing a carrier gas through a capillary gas chromatography column to a detector, introducing a sample to be analyzed into the column and then detecting chromatographically resolved components of interest of the sample, the method having an optimum carrier gas velocity through the column, wherein the improvement of the instant invention is to establish a negative temperature gradient along at least a portion of the longitudinal length of the capillary gas chromatography column and to flow the carrier gas through the capillary gas chromatography column at less than the optimum carrier gas velocity.