# US 5,707,516 A · Column packings for liquid chromatography

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- Number: US 5,707,516 A
- Document ID: US5707516A
- Status: Granted
- Kind: A
- Application number: 08/722,634
- Filed: 1996-09-27
- Granted: 1998-01-13
- Earliest claimed: 1994-07-14
- Assignees: Snow Brand Milk Products Co., Ltd.
- Inventors: Akira Tomizawa; Akinori Shigematsu; Hisashi Matsuda; Naoki Koga; Keisuke Hisada
- Web page: https://patentgrep.com/patent/US5707516A

## CPC

- B01D 15/08: Selective adsorption, e.g. chromatography
- B01D 15/22: relating to the construction of the column
- B01J 20/10: comprising silica or silicate
- B01J 20/12: Naturally occurring clays or bleaching earth
- B01J 20/28023: {Fibres or filaments (fibres or filaments in the form of membranes B01J20/28038; B01J20/28007 takes precedence)}
- B01J 20/28078: {Pore diameter}
- B01J 20/283: based on silica
- B01J 20/3078: {Thermal treatment, e.g. calcining or pyrolizing}
- B01J 2220/54: Sorbents specially adapted for analytical or investigative chromatography
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

Column packings for liquid chromatography comprising porous granules which have hydrophilic surfaces prepared by calcining a crystalline clay mineral having a fibrous structure. Median pore diameter of the porous ceramic granules is in the range of from 0.001 .mu.m to 0.01 .mu.m. The crystalline clay mineral can be sepiolite or attapulgite. The column packings for liquid chromatography have high mechanical strength, are presssure resistant and very stable to elutants having a high pH value and/or a high polarity so that the separating characteristics thereof are not changed even after long use.

## Claims

### Claim 1

Column packings for liquid chromatography comprising porous ceramics granules which have hydrophilic surfaces prepared by the steps comprising:
(1) calcining a crystalline clay mineral having fibrous structure at a temperature of from 100.degree.-1200.degree. C.;
(2) treating with an acid to remove alkali metal oxides and convert a portion of crystalline SiO.sup.2 in the mineral to a non-crystalline form to produce pores in the mineral of 0.1 .mu.m or less, the amount of MgO contained in the mineral after acid treatment being 30 wt. % or less;
(3) calcining a second time at a temperature of from 100.degree.-1200.degree. C. to avoid any decrease in pore volume, the resultant packing having an SiO.sup.2 content of 60 wt. % or more thereby rendering the packing suitable as an HPLC stationary phase.

### Claim 2 (depends on 1)

The column packings for liquid chromatography of claim 1, wherein said fibrous structure is a fibrous crystal structure containing uniform size intracrystalline tunnels parallel with the fiber.

### Claim 3 (depends on 1)

The column packing for liquid chromatography of claim 1, wherein median pore diameter of the porous ceramics granule is in the range of from 0.001 .mu.m to 0.1 .mu.m.

### Claim 4 (depends on 1)

The column packings for liquid chromatography of claim 1, wherein the crystalline clay mineral is sepiolite or attapulgite.

### Claim 5 (depends on 1)

The column packings for liquid chromatography of claim 1, wherein SiO.sub.2 content of the porous ceramics granule is 60 wt. % or more.

### Claim 6 (depends on 1)

The column packings for liquid chromatography of claim 1, wherein MgO content of the porous ceramics granule is 30 wt. % or more.

### Claim 7 (depends on 1)

The column packings for liquid chromatography of claim 1, wherein SiO.sub.2 content of the porous ceramics granule is 60 wt. % or more and MgO content of the porous ceramics granule is 30 wt. % or less.