Separation system, components of a separation system and methods of making and using them
Permeable polymeric monolithic materials are prepared in a column casing. In one embodiment, the permeable polymeric monolithic materials are polymerized while pressure is applied through a piston having a smooth piston head in contact with the polymerization mixture. The pressure eliminates wall effect and changes the structure in the column. Similarly, some columns that have a tendency to swell in the presence of aqueous solutions and pressurized while the solution is applied to prevent swelling and wall effect. This procedure also changes the structure in the column. The size of the separation effective openings can be controlled by the amount of the pressure and pores eliminated. Uniformity in the direction flow is improved by controlling polymerization with radiation rather than with conducted heat.
1. A method of making a monolithic chromatographic column comprising the steps of:
preparing a polymerization mixture including at least one vinyl monomer, an initiator, and a porogen;
inserting said polymerization mixture into the walls of a chromatographic column
polymerizing said polymer mixture under a pressure of at least 80 psi during at least part of said polymerization, whereby sufficient pressure is applied to prevent voids from being formed caused by vacuum due to shrinkage during polymerization in a temperature controlled chamber during at least part of the time pressure is being applied to the polymerization mixture to form a polymer plug; and
washing the polymer plug to remove the porogen.
2. The method of claim 1 in which polymerizing is performed under a pressure of at least 80 psi during at least part of said polymerizing.
3. The method of claim 1 in which polymerizing is performed under a pressure of at least 150 psi during at least part of said polymerizing.
4. The method of claim 1 in which polymerizing is performed under a pressure of at least 180 psi during at least part of said polymerizing.
5. The method of claim 1 in which the pressure is applied in intervals of increasing pressures.
6. The method of claim 1 in which said pressure is sufficient to prevent voids from being formed inside the polymer plug.
7. The method of claim 1 in which said controlled elevated temperature is increased gradually during polymerization by controlling the temperature on the outside of the chamber.