LC-Column with Dynamic-Axial Compression (DAC)

Abstract

A separating column for use with a filling tube to prepare for chromatography is disclosed. The separating column includes an axially movable spring stamp; and a plurality of springs coupled to the stamp. Moreover, the stamp is depressed directly into the column tube during column packing via the filling tube. Additionally, the stamp is fixed in the column tube while maintaining the packing pressure so that the springs are compressed during the packing process and press the stamp permanently and dynamically onto a chromatographic bed.

Claims

1. A separating column for use with a filling tube to prepare for chromatography, the separating column comprising: an axially movable spring stamp; and a plurality of springs coupled to the stamp, the stamp being depressed directly into the column tube during column packing via the filling tube; and the stamp being fixed in the column tube while maintaining the packing pressure so that the springs are compressed during the packing process and press the stamp permanently and dynamically onto a chromatographic bed.

2. The separating column according to claim 1, wherein the plurality of springs hold the stamp in a fixed position inside the column tube.

3. The separating column according to claim 1, wherein the plurality of springs are comprised of stainless steel.

4. The separating column according to claim 1, further comprising a plurality suspension elements backing the stamp.

5. The separating column according to claim 1, wherein a DAC separating column is removed from the filling tube after a packing process.

6. The separating column according to claim 2, further comprising a plurality of spacers that comprise a plurality of half shells holding the spring stamp in the fixed position.

7. A liquid chromatography column for use with a filling tube containing a particle-liquid mixture and a packing apparatus pressing the particle-liquid mixture from the filling tube into the liquid chromatography column, the liquid chromatography column comprising: a column tube for containing a chromatographic packing material formed from the particle-liquid mixture; and a column inlet coupled to the column tube, the column inlet comprising: a plurality of covers coupled to the column tube; a stamp axially movable relative to the covers, with the stamp being pushed by the packing apparatus onto the chromatographic packing material; a plurality of spacers positioned between the stamp and the covers to hold the stamp at a fixed position in the column tube to compress the chromatographic packing material when the packing apparatus is retracted from the column tube; and a plurality of springs adapted to press the stamp onto the chromatographical packing material when the chromatographical packing material shrinks.

8. The liquid chromatography column according to claim 7, wherein the covers comprise a pair of open cover halves inserted around the packing apparatus to form an inner opening with the packing apparatus disposed in the inner opening.

9. The liquid chromatography column according to claim 7, wherein the spacers comprise a pair of open half shells inserted around the packing apparatus.

10. The liquid chromatography column according to claim 7, further comprising a first retaining ring positioned between the stamp and the plurality of springs, and a second retaining ring positioned between the plurality of spacers and the plurality of springs.

11. A method for preparing a liquid chromatography column having a column tube containing a chromatographic packing material and a column inlet coupled to the column tube, the column inlet comprising a plurality of covers, a stamp axially movable relative to the plurality of covers, a plurality of spacers, and a plurality of springs, the method comprising the steps of: filling the column tube with a particle liquid mixture; compressing, with a packing apparatus, the particle liquid mixture to form a chromatographic packing material within the column tube; inserting a plurality of spacers between the stamp and the covers to hold the stamp at a fixed position in the column tube to compress the chromatographic packing material when the packing apparatus is retracted from the column tube.

12. The method according to claim 11 further comprising the step of pressing, with the springs, the stamp onto the chromatographical packing material when the chromatographical packing material shrinks.

13. The method according to claim 11 further comprising the step of coupling the plurality of covers to the column tube and around the packing apparatus to define an inner opening with the packing apparatus positioned within the inner opening.

14. The method according to claim 11 further comprising the step of inserting the plurality of spacers around the packing apparatus, such that the spacers are positioned between the stamp and the plurality of covers to hold the stamp at a fixed position relative to the covers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings show:

[0038] FIG. 1: filling apparatus with assembled DAC column and filling tube

[0039] FIG. 2: ready packed DAC column with steel springs

[0040] FIG. 3: DAC column stamp before (FIG. 3a) and after (FIG. 3b) assembly with steel springs and spring retaining rings

[0041] FIG. 4: column cover halves with inner opening

DETAILED DESCRIPTION

[0042] An LC column generally consists of the column tube which contains the actual chromatographic packing (column bed), the column inlet and the column outlet:

[0043] The column inlet of this new invention consists of the following parts: a column stamp (f) with frit (g) and seals (h), the springs (m), the spring retaining rings (r), a flange pull ring (d), the two column cover halves (b) and the flange screws (c).

[0044] The column cover halves are shown in FIG. 4 in plan view (4a) and in cross-section (4b). The half-shells are shown in FIG. 2(i) in plan view and in longitudinal section.

[0045] Located between the two column cover halves (b) and the column stamp (f) are the springs, delimited at the top and bottom by a spring retaining ring (r). In addition, variously many half-shells (i) can be used for bridging between column cover halves (b) and upper spring retaining ring.

[0046] The column cover halves contain an inner opening (e) for the push rod of the packing apparatus (s) which presses the column stamp out from the filling tube (t) into the actual column (j).

Operating Mode of an LC Column

[0047] In working use a liquid eluent is guided via the inlet capillary (a) into the column tube with column packing (k). The eluent leaves the column again via the outlet capillary (l).

Packing Process of a DAC Column (FIG. 1)

[0048] By means of the push bar (s) of a high-pressure packing pump the column stamp (f) backed with springs (m) is pressed out from the filling tube (t) into the column tube (j), where it is finally fixed.

[0049] For fixing the column stamp still under high pressure must be stopped, i.e. before the push bar retracts by placing two half-shells (FIG. 1, i) around the tapered upper part of the stamp above the upper spring retaining ring (r) and then fixing these with the two column cover halves (b) and screws (c) on a flange pull ring (d) which is fastened to the outside of the column tube.

[0050] During the high-pressure packing process the springs are compressed so that they subsequently press permanently dynamically onto the column bed with the stored relaxation force. The springs must be constructed so that they can be compressed by the high packing pressure during the column packing but not by the lower working pressure during the subsequent separations.

[0051] With the construction and procedure presented here, it is ensured that the stamp can no longer be pressed back by the packing (k) under tension. The pressure originally applied by the push bar is absorbed by the column cover halves, the half shells, the compressed springs, the two spring retaining rings, the flange pull ring and the flange cover screws.

[0052] The chromatographic packing (k) thus remains under permanent dynamic axial compression and cannot expand and relax again.

[0053] The subsequent retraction of the push rod is necessary to be able to remove the column from the packing stand. This is not possible with the hydraulic dynamic DAC columns without compression springs. Here the hydraulic apparatus must press permanently and dynamically onto the column packing for which the columns must remain in the packing state.

REFERENCE LIST

[0054] FIG. 1: column packing state for the packing of DAC columns with filling tube [0055] s=Push bar [0056] t=Filling tube [0057] j=Column tube [0058] f=Column stamp [0059] u=Coupling point of filling tube and column tube [0060] l=Column outlet [0061] k=Column packing [0062] g=Stamp frit [0063] m=Springs

[0064] FIG. 2: DAC column with spring compression technique and two built-in half shells [0065] a=Inlet capillary [0066] b=Column cover halves with inner opening [0067] c=Flange cover screws (not all indicated) [0068] d=Flange pull ring [0069] e=Column cover opening for hydraulic push bar (not visible) [0070] f=Stamp [0071] g=Stamp frit [0072] h=Stamp seal [0073] i=Support elements (half shells) [0074] j=Column tube [0075] k=Column packing [0076] l=Column outlet [0077] m=Springs

[0078] FIG. 3: Spring stamp construction: before (3a) and after (3b) assembly [0079] r=Spring retaining rings [0080] m=Steel springs [0081] f=Stamp

[0082] FIG. 4: column cover halves [0083] 3a: Plan view [0084] p=Screw holes [0085] e=Opening in column cover halves for push bar [0086] 3b: Side view of column cover halves [0087] p=Screw holes [0088] q=Overlap position of column cover halves