Liquid purification or separation – With means to add treating material – Chromatography
Reexamination Certificate
1997-08-13
2001-08-28
Therkorn, Ernest G. (Department: 1723)
Liquid purification or separation
With means to add treating material
Chromatography
C210S635000, C210S656000
Reexamination Certificate
active
06280616
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a column for liquid chromatography.
1. Description of Known Techniques
When practicing liquid chromatography on a porous matrix, a liquid containing a dissolved compound is allowed to pass through the matrix, wherewith the compound flows through the matrix while passing through one or more adsorption/desorption stages.
Matrices intended for liquid chromatography are normally comprised of particles, e.g. beads, that are packed together in a column tube to form a bed. The bed is normally held in place in the tubular column with the aid of two adapters, each covering a respective end of the bed and therewith also the cross-sectional area of the column. One of the adapters will often include an inlet for elution agent which prior to penetrating the matrix bed passes through a perforated plate which distributes the flow uniformly over the end area of the bed. The other adapter has an outlet for elution agent, which prior to entering the outlet also passes through a perforated plate which gathers the flow uniformly across the end area of the bed prior to the elution agent exiting through the outlet. It is normal to place a very fine net between the perforated plate and the gel bed, to prevent the ingress of gel material into respective adapters. Examples of perforated plates are filter plates, gratings, coarse nets, apertured plates and discs.
With the intention of minimizing diffusion and zone spreading during chromatography, the perforated plate, either with or without a fine net, is placed tightly against the inlet area of the bed at respective ends of the column. This is done to obviate the risk of particles swirling up from the bed.
According to known technique, perforated plates are placed against the gel bed and immediately adjacent the end-plate of respective adapters.
2. The Problems of Known Techniques
Conventional perforated plates, such as gratings, etc., have been found to present problems in large scale chromatographic processes in which the gel matrix consists of small beads, which require greater bed packing pressures and are operated at high rates of flow. By large-scale columns is meant here column tubes that have a diameter greater than or equal to 50 mm. A test which functions well on a small scale will often present problems in large-scale chromatography performed under the aforesaid conditions.
More specifically, the earlier known perforated plates impede the radial flow of eluting solution and sample solution respectively in the end-areas of the column, giving rise to an uneven plug flow. This uneven plug flow will often result in a more rapid flow in the middle of the column and slower flow out towards the periphery of the gel-bed cross-section. This is shown in the chromatogram by broad peaks with high degrees of dilution. The plate number of the column will therewith be lowered. Because of the high packing pressure necessary under these conditions, the conventional perforated plates are pressed tightly against the adapter end-plate.
DISCLOSURE OF THE INVENTION
It has now been found that a more uniform plug flow and an increase in plate number can be achieved in large-scale chromatography when a liquid gap is provided between the adapter end-plate and the perforated plate during the chromatographic process. This gap is obtained by providing a perforated plate with projections which function to generate a gap, in addition to openings. The positive effect obtained is because liquid that enters the adapter is spread radially through the perforated plate and penetrates the matrix, through the plate openings, in a continuous vertical layer across the end-area of the matrix, resulting in a uniform plug flow and a higher bottom number.
The inventive liquid-chromatographic column is comprised of a tube which contains a chromatographic gel matrix and an adapter placed at the inlet and the outlet of the column respectively. The invention is characterized in that at least one of the adapters, preferably the inlet adapter, includes a perforated plate and an end-plate, and in that a gap is formed between the end-plate and the perforated plate.
REFERENCES:
patent: 3682315 (1972-08-01), Haller
patent: 3796657 (1974-03-01), Pretorius
patent: 3926800 (1975-12-01), Stephens
patent: 4470910 (1984-09-01), Quemerais et al.
patent: 4557830 (1985-12-01), Onitsuka et al.
patent: 4582608 (1986-04-01), Ritacco
patent: 4587014 (1986-05-01), America
patent: 4732687 (1988-03-01), Muller
patent: 4737292 (1988-04-01), Ritacco
patent: 4743373 (1988-05-01), Rai
patent: 4882047 (1989-11-01), Shalon
patent: 4894152 (1990-01-01), Colvin
patent: 5141635 (1992-08-01), LePlang
patent: 5167810 (1992-12-01), Vassarotti
patent: 5282973 (1994-02-01), Mann
patent: 5316821 (1994-05-01), Otani
patent: 5324426 (1994-06-01), Joseph
patent: 5338448 (1994-08-01), Gjerde
patent: 5772875 (1998-06-01), Petterson
patent: 2248027A (1992-03-01), None
Birch & Stewart Kolasch & Birch, LLP
Pharmacia Biotech AB
Therkorn Ernest G.
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