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US 4,902,413 AGranted
Organic-based porous microspheres for HPLC
AssigneeE. I. Du Pont de Nemours and Company
InventorsRichard W. Stout, Henry J. Leibu
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Abstract
Porous organic microspheres for use in HPLC are formed by coacervating a colloidal silica sol in a uniform mixture of the sol and a polymerizable organic material. The silica particles which formed the sol are removed from the microspheres with ammonium bifluoride. The remaining organic microspheres are rigid, have uniform pore sizes and distribution, and do not swell or shrink in the presence of the solvents used in HPLC.
Claims8
A process for forming porous organic microparticles comprising the steps of:
- a. forming a sol of inorganic colloidal particles in a polar liquid, the colloidal particles having hydroxylated surfaces and being dispersible in the polar liquid;
- b. forming a mixture of the sol with a polymerizable organic material comprising formaldehyde and a second organic material selected from the group consisting of urea and melamine;
- c. polymerizing the organic material in said mixture to cause coacervation of the organic material and said colloidal particles into microparticles having a diameter of about 0.5 to about 20 microns;
- and
- d. subjecting the microparticles so formed to a solution of a reagent of suitable composition and of sufficient strength to remove all of the inorganic component.
2 more elements
Dependencies are inferred from the claim text.