Charles J Oberhauser

59683678, Oct 19, 1999

Jan 7, 1998

9/003856

Hubert M. Quinn - Brighton MA
Rebecca A. Menapace - Framingham MA
Charles J. Oberhauser - Belmont MA

Cohesive Technologies, Inc. - Franklin MA

B01D 1508

210656

High pressure liquid chromatographic apparatus in which a fluid mixture containing at least one solute that is reactive with chromatographically reactive surfaces in the column is loaded into the column, and a number of plugs of different eluant fluids are injected into that column. The injections are made in a manner that minimizes the amount of eluant required. In one embodiment, the injections are made to insure that flow of at least the eluant fluids through the column will occur, preferably with a substantially flat wave front, at speeds corresponding to reduced velocities greater than about 5,000, i. e. at flow rates sufficient to induce turbulent flow in those fluids, thereby minimizing the time required for the entire succession of mixture and eluant fluids to traverse the column. In other embodiments, the injections are made substantially simultaneously at spatially separated points adjacent the entrance to the column or are made in sequence to a single location adjacent the entrance to the column, in either case the fluids then tend to travel through the column at a common group velocity as closely bunched fluid plugs.

57954690, Aug 18, 1998

Jan 21, 1997

8/785324

Hubert M. Quinn - Brighton MA
Rebecca A. Menapace - Framingham MA
Charles J. Oberhauser - Belmont MA

Cohesive Technologies, Inc. - Acton MA

B01D 1508

2101982

High pressure liquid chromatographic apparatus in which a fluid mixture containing at least one solute that is reactive with chromatographically reactive surfaces in the column is loaded into the column, and a number of plugs of different eluant fluids are injected into that column. The injections are made in a manner that minimizes the amount of eluant required. In one embodiment, the injections are made to insure that flow of at least the eluant fluids through the column will occur, preferably with a substantially flat wave front, at speeds corresponding to reduced velocities greater than about 5,000, i. e. at flow rates sufficient to induce turbulent flow in those fluids, thereby minimizing the time required for the entire succession of mixture and eluant fluids to traverse the column. In other embodiments, the injections are made substantially simultaneously at spatially separated points adjacent the entrance to the column or are made in sequence to a single location adjacent the entrance to the column, in either case the fluids then tend to travel through the column at a common group velocity as closely bunched fluid plugs.

6190550, Feb 20, 2001

Sep 30, 1999

9/408714

Charles J. Oberhauser - Belmont MA

Cohesive Technologies, Inc. - Frankline MA

B01D 1508

2101982

A method of monitoring performance of liquid chromatography apparatus comprising an elongated chromatography column and having a conduit coupled to the column inlet for introducing a flow of liquid into said column preferably at very high pressure. Variations in a selected electromagnetic property, such as the electrical conductivity, of the liquid flow are measured, preferably in the conduit. Apparatus is configured so that respective volumes of sample liquid and eluant may be introduced into the conduit sequentially or substantially simultaneously with substantially no band-spreading when flowing through the conduit into the column. A pair of electrically conductive electrodes, coupled to metering means, are positioned at two spaced-apart locations within the conduit and are electrically insulated from each other and from the ends of the conduit.