The Dow Chemical Company

Thomas L Peters

Timothy S Stevens

Curtis D Pfeiffer

Terry J Nestrick

Terrence McCabe

Philip J Savickas

Paul L Morabito

Joseph F Hiller

Nile Nelson Frawley

Lawrence W Nicholson

Steven J Gluck

Jose B Esquivel H

David R Albers

Lester L Lamparski

A chemical analysis method for determining chemically related differences between subject biological material such as genetically modified plant material and control biological material such as genetically unmodified plant material, which method includes at least the following six steps. The first step is to contact the subject biological material with a fluid extractant, such as a mixture of water, isopropanol and potassium hydroxide, to produce a fluid extract of the subject biological material. The second step is to contact the control biological material with the fluid extractant to produce a fluid extract of the control biological material. The third step is to chromatograph the fluid extract of the subject biological material, for example, gas or fluid chromatography, to produce a chromatogram of the fluid extract of the subject biological material. The fourth step is to chromatograph the fluid extract of the control biological material to produce a chromatogram of the fluid extract of the control biological material. The fifth step is to determine the differences between the chromatograms, for example, by using the method of U.S. Pat. No. 5,592,402, to identify at least one outlier peak. The sixth step is to determine the chemical identity of the outlier peak, for example, using gas chromatography/mass spectroscopy analysis of the outlier peak.

Method for chemical analysis of biological material

A method for on-column injection of large sample volumes using the retention gap technique in capillary gas chromatography for sample components of interest that would be obscured by the large solvent peak otherwise inherent in the technique. This interference from the large solvent peak is removed by venting carrier flow from the retention gap to waste for a limited time, long enough to discard much of the solvent without serious loss of the sample component of interest.

Vented retention gap capillary gas chromatography method

The overall mass transport efficiency of hollow fiber membrane separation cells is increased by introducing segmented flow into the bores of the fibers. The invention is preferably practiced by dispersing a gas segmentation phase into a continuous liquid phase and feeding the dispersion into the bores of the fibers to form alternating flowing segments of gas and liquid.

Apparatus for membrane-permeation separations using segmented flow

Apparatus and method for membrane-permeation separations using segmented

An improved process for etching (eroding) the inner surface of a glass capillary column in which ammonium bifluoride in liquid methanol is passed slowly through the capillary bore for a prolonged period, followed by rinsing with methanol, thereafter a gradually diluting rinse mixture of methanol and water, and finally a pure water rinse. A very fine structured etch of uniform depth is produced with no apparent air entrainment making the columns suitable for all standard stationary phase coating procedures.

Process for etching glass capillaries for chromatography

In the production of a wall coated open tubular capillary chromatographic column, improved deactivation of the inner surface of a glass or fused silica capillary tube prior to coating with stationary phase is obtained by a multi-step process whereby siloxane polymer molecules are chemically bonded to the capillary inner surface. The process comprises multiple cycles of successive reactions with silicon tetrachloride and a diorganodichlorosilane vapor with intermediate hydrolyses and a final capping reaction with a triorganochlorosilane. The deactivated surface is adapted to coating with an apolar liquid stationary phase.

Coated capillary chromatographic column

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Midland, MI, United States of America

Thomas L Peters