Chromatography columns with cast porous plugs and methods of fabricating same
AssigneeLee Scientific, Inc.
InventorsHernan Cortes, Curtis D. Pfeiffer, Bruce E. Richter, Timothy S. Stevens
Life of this patent
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Abstract
Porous ceramic plugs are cast in place in chromatographic columns in order to provide supports for chromatographic beds in liquid chromatography devices and restrictors in supercritical fluid chromatographic devices. The supports are cast in place by fusing a silicate containing solution, such as one containing potassium silicate, which has been drawn into the outlet end of the column.
Claims42
In a process for fabricating a chromatographic column wherein the column includes a capillary tube of a selected material, the tube having an open end and an inner wall having a silica component, the process comprising the steps of:
- (a) providing a chemically fusible material which is microporous upon casting and which adheres to the specific material of the tube upon fusing, which chemically fusible material comprises a composition having a silicate component;
- (b) depositing a quantity of the chemically fusible material in the tube;
- and
- (c) casting a plug in situ by fusing the material within the tube and chemically adhering the material to the inner wall of the tube to form a solid microporous mass having a length along the tube within the range of between less than 4 centimeters and more than 10 microns.
In a chromatographic column used for supercritical fluid chromatography, a tube having a silica component and having an inner wall and containing a chromatographic bed or a liquid stationary phase coated or bonded to the inner wall, an inlet end and an outlet end, the outlet end including a restrictor, which restrictor allows controlled expansion of a supercritical fluid;
- the restrictor being configured as a plug of microporous ceramic material having a silica component and having a length along the tube within the range of between less than 4 centimeters and more than 10 micron and which has been cast in situ and which is chemically adhered to the inner wall of the tube, whereby:
- a multitude of paths are provided for solutes to exit from the column, the distance over which decompression occurs is controlled, and molecular association and condensation is minimized within the plug.
In a chromatographic column, a tube having a silica component and containing a chromatographic bed and having an inner wall, inlet end and an outlet end, a bed support positioned at the outlet end for supporting the chromatographic bed;
- the bed support being a plug of porous ceramic material having a silica component and having a length along the tube within the range of between less than 4 centimeters and more than 10 microns which has been cast in situ at the outlet end and chemically adhered to the inner wall of the tube.
A chromatographic apparatus for retention of selected material within a tube comprising:
- a tube having a silica component;
- and
- a plug having a silica component and having a length along the tube within the range of between less than 4 centimeters and more than 10 microns and disposed within the interior of the tube, said plug being made of a fusible microporous material such that said selected materials can be retained within said tube, wherein said plug is chemically fused to the interior wall of said tube.
A chromatographic apparatus including means for controlling pressure change between the interior and exterior of a tube comprising:
- a tube having a silica component;
- and
- a plug having a silica component and having a length along the tube within the range of between less than 4 centimeters and more than 10 microns and disposed within the interior of the tube, said plug being made of a fusible microporous material such that a controlled pressure differential can be created between the interior and exterior of the tube, wherein said plug is chemically fused to the interior wall of said tube and wherein said plug is sized and dimensional so that it is capable of controlling pressure change between the interior and exterior of said tube.
Dependencies are inferred from the claim text.