Abstract: A replaceable cartridge column for use in high pressure liquid chromatograph pumping systems including a solid tube having a small bore therethrough carrying a packing material. The tube and terminated by a recess at each end which extends from the rim at the end of the tube inwardly and in communication with the bore. A plastic seal plug is disposed in the recess at each end to extend slightly beyond excess the length of the tube when so disposed and carries at its outer end a coaxial frit filter. The recess is provided with a flat bottom and the plastic plug has a corresponding bottom constructed to be positioned in face-to-face sealing opposition to fluid leakage and having further a flat sealing surface at its other end to engage a sealing surface of an end fitting of the liquid chromatographic pumping system and to provide a first, primary seal therewith independent of the rim of the column tube.

Abstract: A coupling for high pressure liquid chromatographic columns of any length, individually, or by union of two columns together, in which an end fitting carries a secondary seal together with internal means for retaining the seal in place. The end fitting is designed as a unitary assembly wherein the secondary seal is secured into the end fitting as a unitary assembly of parts without the use of screw threaded members. A special screw and nut configuration of end fittings permits the same design to be used for columns of extremely short lengths.