Chromatographic column and methods for controlling sorbent density
Disclosed herein are apparatus and methods for mitigating column bed compression over time. This invention provides for an improved column design and method of controlling bed density in a chromatographic column using a protruding portion of a filter assembly. The invention results in a higher sorbent bed density than can normally be achieved using a fixed length column of conventional design. The invention may be implemented as a unique filter assembly or as a column tailored for the application and a matching filter assembly.
1. A method of constructing a chromatography column, comprising:
providing a column tube, wherein said column tube has a first end, a second end, an interior wall and an exterior wall, wherein said tube has a tube chamber and wherein said tube has a recess machined in said first end;
securing a medium collar having a top end, a bottom end, a substantially smooth inner surface, and an articulated external surface in said recess with said external surface abutting said recess, said inner surface substantially aligned with said interior wall and said top end aligned with said first end, wherein said tube with said medium collar installed has an interior chamber;
affixing an outlet filter assembly to said second end of said column tube,
wherein said outlet filter assembly has a second housing for mounting to said second end and a fluid outlet that is in fluid communication with said housing, wherein a first column sorbent bed volume is defined by said interior chamber and said affixed outlet filter assembly;
adding a separation medium into said interior chamber of said column tube;
inserting an inlet filter assembly onto said first end, said inlet filter assembly having a first housing for mounting to said first end, a fluid inlet that is in fluid communication with said first housing, and end seal fitted to said first housing for mating with said tube first end, and a protruding portion that extends from said first housing into said interior chamber, said protruding portion cooperating with said medium collar to retain said separation medium in said chamber; and
affixing said inserted inlet filter assembly to said first end, wherein a second column sorbent bed volume is defined by said tube affixed to said outlet filter assembly and said inlet filter assembly, and wherein said second bed volume is less than said first bed volume.
2. The method of claim 1 wherein said adding operation is followed by packing said separation medium in said interior chamber.
3. The method of claim 1 wherein said adding operation is followed by passing a fluid through said separation medium to compress said medium.
4. The method of claim 1 wherein pressure is applied to said inlet filter assembly to effect said insertion.