US5777099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
RNA separation
Assignee: Biotecx Laboratories Inc
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Filing: 1996-09-04
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Granted: 1998-07-07
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Expires: 2016-09-04
Abstract
Abstract An improved process for the separation of RNA from a liquid sample of biological origin containing RNA comprises (a) intimately contacting the sample with a two-phase composition wherein the upper phase is predominately phenol and the lower phase is an aqueous solution comprising at least one water-soluble guanidinium salt, a buffer and urea, the water content of the aqueous phase being relatively low, (b) adding a relatively dense water-insoluble solvent and (c) recovering RNA from the resulting aqueous phase.
Inventors
- 👤 Manmohan Mehra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:35
CPC Classifications
C; C12; C12N; C12N15/00; C12N15/09; C12N15/10; C12N15/1003
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
103 words
In the process of separating RNA from biological samples containing RNA by contacting the sample with a two-phase composition wherein the upper phase is predominately phenol and the lower phase is an aqueous solution containing at least one water-soluble guanidinium salt, a buffer and urea, the improvement which comprises separating RNA from a substantially liquid biological sample with the two-phase composition wherein the phenol is present in a quantity not more than about 40% by weight based on total composition and the water is present in a quantity from about 10% by weight to about 25% by weight, inclusive, based on total composition.
Claim 2
Dependent Claim
103 words
In the process of separating RNA from biological samples containing RNA by contacting the sample with a two-phase composition wherein the upper phase is predominately phenol and the lower phase is an aqueous solution containing at least one water-soluble guanidinium salt, a buffer and urea, the improvement which comprises separating RNA from a substantially liquid biological sample with the two-phase composition wherein the phenol is present in a quantity not more than about 40% by weight based on total composition and the water is present in a quantity from about 10% by weight to about 25% by weight, inclusive, based on total composition.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the substantially liquid sample is blood serum.
Claim 4
Dependent Claim
28 words
The process of claim 2 wherein the phenol is present in a quantity from about 30% by weight to about 38% by weight, inclusive, based on total composition.
Claim 5
Dependent Claim
28 words
The process of claim 3 wherein the water is present in a quantity from about 15% by weight to about 23% by weight, inclusive, based on total composition.
Claim 6
Dependent Claim
80 words
A two-phase liquid composition wherein the upper phase is predominately phenol and the lower phase is an aqueous solution of at least one water-soluble guanidinium salt, a buffer and urea, the phenol is present in a quantity of from about 30% by weight to about 38% by weight, inclusive, based on total composition, and the water of the aqueous phase is present in a quantity from about 10% by weight to about 25% by weight, inclusive, based on total composition.
Claim 7
Dependent Claim
80 words
A two-phase liquid composition wherein the upper phase is predominately phenol and the lower phase is an aqueous solution of at least one water-soluble guanidinium salt, a buffer and urea, the phenol is present in a quantity of from about 30% by weight to about 38% by weight, inclusive, based on total composition, and the water of the aqueous phase is present in a quantity from about 10% by weight to about 25% by weight, inclusive, based on total composition.
Claim 8
Dependent Claim
43 words
The composition of claim 5 wherein the at least one water-soluble guanidinium salt is at least one of guanidinium thiocyanate and guanidinium chloride in a total amount of from about 15% by weight to about 25% by weight, inclusive, based on total composition.
Claim 9
Dependent Claim
18 words
The composition of claim 6 wherein the buffer is an alkali metal salt of a weak organic acid.
Claim 10
Dependent Claim
24 words
The composition of claim 7 wherein the alkali metal moiety is sodium and the organic acid is citric acid, acetic acid or tartaric acid.
Claim 11
Dependent Claim
11 words
The composition of claim 8 wherein the buffer is sodium citrate.
Claim 12
Dependent Claim
28 words
The composition of claim 7 wherein the urea is present in a quantity of from about 5% by weight to about 15% by weight, based on total composition.
Claim 13
Dependent Claim
17 words
The composition of claim 10 wherein the predominately phenol phase is at least 98% by weight phenol.
Claim 14
Dependent Claim
33 words
The composition of claim 10 wherein the water of the aqueous phase is present in a quantity of from about 15% by weight to about 23% by weight, inclusive, based on total composition.
Claim 15
Dependent Claim
70 words
A process of separating RNA from a liquid sample of biological origin containing RNA which comprises intimately contacting the sample with the composition of claim 4, adding to the resulting mixture a water-insoluble solvent, thereby forming an aqueous phase containing RNA and an organic phase containing other components of the liquid sample, separating the aqueous phase containing RNA from the remaining mixture, and recovering the RNA from the aqueous phase.
Claim 16
Dependent Claim
14 words
The process of claim 13 wherein the liquid sample of biological origin is serum.
Claim 17
Dependent Claim
11 words
The process of claim 14 wherein the serum is blood serum.
References Cited (Backward Citations)
US3389133A
Cited
US4830969A
Cited
US4843155A
Cited
US5234809A
Cited
US5130423A
Cited
US5393672A
Cited
US5422241A
Cited
EP0554034A1
Cited
US5346994A
Cited
US5300635A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-07-06 | 2002-01-05 | 2002-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-06 | 2006-01-05 | 2006-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-06 | 2010-01-05 | 2010-07-07 | $7700.00 | Window Closed / Lapsed |