Abstract: To provide a cation exchanger for liquid chromatography having a high retention for an object to be separated or analyzed, a sufficient binding capacity for the object, a high resolution and mechanical strength, and a low operation pressure. A cation exchanger for liquid chromatography, comprising non-porous particles and, immobilized to the surface thereof, a polyacrylic acid into which a dicarboxylic acid compound having an amino group is introduced by an amide bond.

Abstract: Crosslinked (meth)acrylamide particles in the form of substantially spherical fine particles having particle sizes of from 1 to 1000 ?m made of a polymer of a N-alkoxymethyl(meth)acrylamide and a polyfunctional unsaturated monomer copolymerizable with the N-alkoxymethyl(meth)acrylamide, wherein the structural units derived from the N-alkoxymethyl(meth)acrylamide are crosslinked by a crosslink having a structure represented by the formula 1 (wherein X is hydrogen or a methyl group, and each of R8 and R9 is another structural unit derived from the N-alkoxymethyl(meth)acrylamide and bonded to the nitrogen atom in another structural unit derived from the N-alkoxymethyl(meth)acrylamide monomer via a methylene group).

Abstract: Crosslinked (meth)acrylamide particles in the form of substantially spherical fine particles having particle sizes of from 1 to 1000 ?m made of a polymer of a N-alkoxymethyl(meth)acrylamide and a polyfunctional unsaturated monomer copolymerizable with the N-alkoxymethyl(meth)acrylamide, wherein the structural units derived from the N-alkoxymethyl(meth)acrylamide are crosslinked by a crosslink having a structure represented by the formula 1 (wherein X is hydrogen or a methyl group, and each of R8 and R9 is another structural unit derived from the N-alkoxymethyl(meth)acrylamide and bonded to the nitrogen atom in another structural unit derived from the N-alkoxymethyl(meth)acrylamide monomer via a methylene group).

Abstract: Monodisperse particles having a particle diameter in the range of about from 1 to 1,000 ?m; a process for easily producing the particles; a column for liquid chromatography which is packed with the particles; and a method of liquid chromatography which comprises using the column. The monodisperse particles are obtained by adding an aqueous emulsion containing a polymerizable monomer to monodisperse polymer seed particles comprising a poly((meth)acrylic ester) containing at least one kind of groups selected from the group consisting of straight-chain alkyl groups having 6 or more carbon atoms, alicyclic alkyl groups having 6 or more carbon atoms, phenyl groups, benzyl groups and halogenated alkyl groups having 3 or more carbon atoms to thereby swell the seed particles and then polymerizing the polymerizable monomer.

Abstract: An anion exchanger comprised of a fine particle having a cured polyethyleneimine surface layer formed on the fine particle surface. The cured polyethyleneimine surface layer is formed by the steps of: (1) dispersing a fine particle having a functional group capable of reacting with polyethyleneimine on the fine particle surface, in an aqueous solution of a crosslinking agent capable of crosslinking polyethyleneimine to prepare an aqueous dispersion of the fine particle; and then, (2) adding the polyethyleneimine and a catalyst for crosslinking the polyethyleneimine in the aqueous dispersion of the fine particle, and carrying a reaction of bonding the polyethyleneimine to the functional group on the fine particle surface and a reaction of crosslinking the polyethyleneimine with the crossslinking agent. The anion exchanger is used as a packing for chromatography.

Abstract: A cation exchanger comprised of a fine particle having bound to the surface thereof a polymer having a cation exchanging property, wherein said polymer is selected from (i) polymers prepared by polymerization of an unsaturated carboxylic acid and partially crosslinked with a polymer having a functional group capable of reacting with a carboxylic acid, and (ii) an acrylic acid-maleic acid copolymer. The cation exchanger is produced by the steps of: dispersing fine particles in a solution containing (i) a combination of a polymer prepared by polymerization of an unsaturated carboxylic acid, with a polymer having a functional group capable of reacting with a carboxylic acid, or (ii) an acrylic acid-maleic acid copolymer, to prepare a dispersion of fine particles; removing a liquid medium from the particle dispersion to separate a solid content; and then, heating the solid content in a dried state. The cation exchanger is useful as a packing for chromatography.

Abstract: An anion exchanger which is a fine particle having bound to the surface thereof a polyamine, preferably polyethyleneimine, having a molecular weight of at least 50,000. The anion exchanger can be produced by binding a polyamine having a number average molecular weight of at least 50,000 to a functional group such as an epoxy group, a halogenated alkyl group and/or an aldehyde group, present on the surface of a fine particle. The anion exchanger is useful as a packing for column chromatography.

Abstract: A cation exchanger comprised of a fine particle having bound to the surface thereof a polymer having a cation exchanging property, wherein said polymer is selected from (i) polymers prepared by polymerization of an unsaturated carboxylic acid and partially crosslinked with a polymer having a functional group capable of reacting with a carboxylic acid, and (ii) an acrylic acid-maleic acid copolymer. The cation exchanger is produced by the steps of: dispersing fine particles in a solution containing (i) a combination of a polymer prepared by polymerization of an unsaturated carboxylic acid, with a polymer having a functional group capable of reacting with a carboxylic acid, or (ii) an acrylic acid-maleic acid copolymer, to prepare a dispersion of fine particles; removing a liquid medium from the particle dispersion to separate a solid content; and then, heating the solid content in a dried state. The cation exchanger is useful as a packing for chromatography.

Abstract: An anion exchanger comprised of a fine particle having a cured polyethyleneimine surface layer formed on the fine particle surface. The cured polyethyleneimine surface layer is formed by the steps of: (1) dispersing a fine particle having a functional group capable of reacting with polyethyleneimine on the fine particle surface, in an aqueous solution of a crosslinking agent capable of crosslinking polyethyleneimine to prepare an aqueous dispersion of the fine particle; and then, (2) adding the polyethyleneimine and a catalyst for crosslinking the polyethyleneimine in the aqueous dispersion of the fine particle, and carrying a reaction of bonding the polyethyleneimine to the functional group on the fine particle surface and a reaction of crosslinking the polyethyleneimine with the crossslinking agent. The anion exchanger is used as a packing for chromatography.

Abstract: Monodisperse particles having a particle diameter in the range of about from 1 to 1,000 &mgr;m; a process for easily producing the particles; a column for liquid chromatography which is packed with the particles; and a method of liquid chromatography which comprises using the column. The monodisperse particles are obtained by adding an aqueous emulsion containing a polymerizable monomer to monodisperse polymer seed particles comprising a poly((meth)acrylic ester) containing at least one kind of groups selected from the group consisting of straight-chain alkyl groups having 6 or more carbon atoms, alicyclic alkyl groups having 6 or more carbon atoms, phenyl groups, benzyl groups and halogenated alkyl groups having 3 or more carbon atoms to thereby swell the seed particles and then polymerizing the polymerizable monomer.