Adsorption columns for use in radioimmunoassays

Claim 1

A process for the preparation of a disposable adsorption column useful for radioimmunoassays in a centrifugal field which process comprises the steps of: (1) inserting into a cylindrical column which is open at both ends and has a middle portion of essentially uniform diameter, a bottom protion which tapers to a lesser diameter than said middle portion, and an upper portion which is of a greater diameter than said middle portion, a first porous hydrophilic disc-shaped retaining member comprised of polyethylene and having a porosity of up to about 30 microns and capable of: (a) retaining a separation medium within said column, (b) withstanding a centrifugal filed of at least five times gravity without cracking or bending, and (c) passing liquid at a rate faster than that of said separation medium, said first retaining member having pores sized smaller than the size particles comprising said separation medium and being disposed within said column at a point wherein said middle portion narrows to said lesser diameter; (2) filling said middle portion of said column with an aqueous slurry of a separation medium comprised of a gel in water having a ratio of water to gel of from about 1:1.5 to about 1.5:1, said separation medium capable of selectively retaining one or more components which are admitted to said column, at least about 90 percent of the particles comprising said separation medium sized from about 20 to about 80 microns; (3) inserting into said column a second porous hydrophilic disc-shaped retaining member comprised of polyethylene and capable of: (a) retaining said separation medium within said column, (b) withstanding a centrifugal field of at least five times gravity without cracking or bending, and (c) passing liquid at a rate faster than that of said separation medium, said second retaining member having pores sized smaller than the size particles comprising said separation medium disposed within said column at a point on top of said separation medium approximately wherein said middle portion widens to said greater diameter; (4) admitting sufficient water to the top of said column to prevent said separation medium for drying, and (5) attaching removeable sealing means to both ends of said column.