US5137627A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Deactivated supports for liquid chromatographic separation of silanophiles
Assignee: Sigma-Aldrich Co LLC
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Filing: 1990-05-10
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Granted: 1992-08-11
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Expires: 2010-05-10
Abstract
Abstract Silica gel chromatographic supports surface-modified with (R 1 O) 3-m Si R 2 m (CH 2 ) 3 NH(CH 2 CH 2 NH) n H, in which R 1 is a C 1 -C 5 alkyl, R 2 is methyl or ethyl, and m and n are independently selected from the integers 0, 1 or 2, and further modified chemically to produce reverse-phase character, markedly reduce the interaction between silanophilic analytes and the silanol groups present on the surface of the silica gel through the presence of polar groups, which include the residual unmodified amino and modified amino groups, and which are densely packed near the silica surface. This results in chromatographic elution of basic, silanophilic analytes in efficient, narrow bands similar to those of the less-polar analytes.
Inventors
- 👤 Binyamin Feibush
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:58
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/281; B01J20/286; B01J20/02; B01J20/10; B01J20/103; B01J20/28; B01J20/28002; B01J20/28004; B01J20/28014; B01J20/28047; B01J20/28054; B01J20/28057; B01J20/287; B01J20/291; B01J20/30; B01J20/3092; B01J20/32; B01J20/3202; B01J20/3204; B01J20/3231; B01J20/3242; B01J20/3244; B01J20/3246; B01J20/3257; B01J20/3259; B01J20/3261; B01J2220/00; B01J2220/50; B01J2220/54; B01J2220/58
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
110 words
A process for the preparation of silica gel support suitable for use in reverse-phase liquid chromatographic separations of silanophilic analytes which comprises the steps, carried out in order, of a. reacting a silica gel with 3-aminopropyltrimethyloxysilane as an aminosilylating reagent, b. reacting the resulting aminosilylated surface with palmitoyl chloride, and c. isolating from the reaction mixture a surface-modified silica gel having amino groups or modified amino groups or both densely packed near the silica surface and covalently bonded alkyl groups which impart a reverse-phase character to the silica gel, the silica gel providing a reverse-phase liquid chromatographic support in which interaction between silanophilic analytes and the silica surface is minimized.
Claim 2
Dependent Claim
110 words
A process for the preparation of silica gel support suitable for use in reverse-phase liquid chromatographic separations of silanophilic analytes which comprises the steps, carried out in order, of a. reacting a silica gel with 3-aminopropyltrimethyloxysilane as an aminosilylating reagent, b. reacting the resulting aminosilylated surface with palmitoyl chloride, and c. isolating from the reaction mixture a surface-modified silica gel having amino groups or modified amino groups or both densely packed near the silica surface and covalently bonded alkyl groups which impart a reverse-phase character to the silica gel, the silica gel providing a reverse-phase liquid chromatographic support in which interaction between silanophilic analytes and the silica surface is minimized.
Claim 3
Dependent Claim
21 words
The process of claim 1 wherein the second reagent is reacted with the aminosilylated surface in an aprotic, polar suspending solvent.
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein the suspending solvent is methylene chloride.
Claim 5
Dependent Claim
27 words
The process of claim 2 wherein the second reagent is reacted with the aminosilylated surface in the presence of a scavenger for acid produced in the reaction.
Claim 6
Dependent Claim
10 words
The process of claim 2 wherein the scavenger is 4-dimethylaminopyridine.
Claim 7
Dependent Claim
25 words
The process of claim 1 wherein the silica gel is reacted with the aminosilylating reagent in the presence of a non-reactive solvent at elevated temperature.
Claim 8
Dependent Claim
22 words
The process of claim 6 wherein the non-reactive solvent is toluene and the elevated temperature is the reflux temperature of the toluene.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-11 | 1996-02-10 | 1996-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-11 | 2000-02-10 | 2000-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-11 | 2004-02-10 | 2004-08-11 | $7700.00 | Window Closed / Lapsed |