US4773994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid chromatography packing materials
Assignee: Dow Silicones Corp
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Filing: 1987-06-17
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Granted: 1988-09-27
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Expires: 2007-06-17
Abstract
Abstract Packing materials for use in liquid chromatographic analysis are prepared by contacting a porous support, such as porous silica, with a ketal silane to form ketal blocked diol groups on the surfaces thereof. An end-capping reagent such as a trimethylsilyl reagent may be added. In addition, the ketal blocked diol groups may be further hydrolyzed to diol groups.
Inventors
- 👤 Dwight E. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:26
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/281; B01J20/286; B01J20/287; B01J20/30; B01J20/32; B01J20/3214; B01J20/3225; B01J20/3227; B01J20/3231; B01J20/3242; B01J20/3244; B01J20/3246; B01J20/3257; B01J20/3263; B01D; B01D15/00; B01D15/08; B01D15/26; B01D15/32; B01D15/325; B01D15/34; B01J2220/00; B01J2220/50; B01J2220/54; G; G01; G01N; G01N30/00; G01N30/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
37 words
A reverse phase packing material for liquid chromatographic columns which comprises a porous support having ketal blocked diol groups on the surfaces thereof wherein said ketal blocked diol groups have the formula: ##STR8## wherein m is 1-3.
Claim 2
Dependent Claim
37 words
A reverse phase packing material for liquid chromatographic columns which comprises a porous support having ketal blocked diol groups on the surfaces thereof wherein said ketal blocked diol groups have the formula: ##STR8## wherein m is 1-3.
Claim 3
Dependent Claim
13 words
The packing material of claim 1 wherein said porous support is porous silica.
Claim 4
Dependent Claim
16 words
The packing material of claim 2 wherein said ketal blocked diol groups have the formula ##STR9##
Claim 5
Dependent Claim
20 words
The packing material of claim 3 wherein said porous silica support also has trimethylsilyl end-capping groups on the surfaces thereof.
Claim 6
Dependent Claim
19 words
The packing material of claim 3 wherein said porous silica support also has octadecylsilyl groups on the surfaces thereof.
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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) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |