US4375163A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for on-column detection in liquid chromatography
Assignee: Varian Medical Systems Inc
•
Filing: 1981-01-08
•
Granted: 1983-03-01
•
Expires: 2001-01-08
Abstract
Abstract On-column detection by an optical detector is accomplished with a flexible silica column. The flexible fused silica column has an inner diameter less than 500 μm, an external protective coating with a stripped portion near the end of the column. The stripped portion is placed in the working path of an optical detector in order to detect and resolve the sample.
Inventors
- 👤 Frank J. Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:40
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/60; G01N30/6052; G01N30/6073; G01N30/6078; G01N30/62; G01N30/74; G01N30/6082
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
A method for high resolution on-column detection in high resolution liquid chromatography, comprising: providing a fused silica microcapillary column having an inner diameter less than 500 μm; activating the interior of said column with a chromatographically active material; applying a protective coating to the exterior of said column; removing a segment of said protective coating to expose the underlying segment of said fused silica column; providing an optical chromatographic detector; positioning said exposed segment of said column in the optical path of said detector; flowing a sample containing species to be identified through said column; and detecting separated species as they flow through said exposed segment of said column.
Claim 2
Independent Claim
109 words
A method for high resolution on-column detection in high resolution liquid chromatography, comprising: providing a fused silica microcapillary column having an inner diameter less than 500 μm; activating the interior of said column with a chromatographically active material; applying a protective coating to the exterior of said column; removing a segment of said protective coating to expose the underlying segment of said fused silica column; providing an optical chromatographic detector; positioning said exposed segment of said column in the optical path of said detector; flowing a sample containing species to be identified through said column; and detecting separated species as they flow through said exposed segment of said column.
Claim 3
Dependent Claim
47 words
A method for on-column detection in accordance with claim 1 wherein said step of activating the interior of said column is accomplished by the step of packing said column with a chromatographically active material and wherein said packing is removed within the volume of said exposed segment.
Claim 4
Dependent Claim
38 words
A method for on-column detection in accordance with claim 1 wherein said step of activating the interior of said column is accomplished by the step of coating the inner wall of said column with a chromatographically active material.
Claim 5
Dependent Claim
25 words
A method for on-column detection in accordance with claim 3 in combustion with the step of removing said chromatographically active material along said exposed segment.
Claim 6
Dependent Claim
29 words
A method for on-column detection in accordance with claim 1 wherein said step of providing a chromatographic detector is accomplished by the step of providing an ultraviolet absorbance detector.
Claim 7
Dependent Claim
72 words
Apparatus for on-column detection in high resolution liquid chromatography comprising: a flexible fused silica column having an inner diameter less than 500 μm, said column being chromatographically activated and also having an external protective coating, said external coating having a segment exposed along the end of its length; and an optical chromatographic detector configured to receive said column so that said exposed segment lies in the optical detection path of said detector.
Claim 8
Dependent Claim
72 words
Apparatus for on-column detection in high resolution liquid chromatography comprising: a flexible fused silica column having an inner diameter less than 500 μm, said column being chromatographically activated and also having an external protective coating, said external coating having a segment exposed along the end of its length; and an optical chromatographic detector configured to receive said column so that said exposed segment lies in the optical detection path of said detector.
Claim 9
Dependent Claim
20 words
Apparatus for on-column detection in accordance with claim 6 wherein said exposed segment is less than one centimeter in length.
Claim 10
Dependent Claim
18 words
Apparatus for on-column detection in accordance with claim 6 wherein said optical chromatographic detector is an ultraviolet detector.
Claim 11
Dependent Claim
19 words
Apparatus for on-column detection in accordance with claim 7 wherein said column is packed with a chromatographically active material.
Claim 12
Dependent Claim
23 words
Apparatus for on-column detection in accordance with claim 7 wherein the inner surface of said column is coated with a chromatographically active material.
References Cited (Backward Citations)
US3518009A
Cited
US4207188A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-28 | 1986-08-30 | 1987-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-28 | 1990-08-30 | 1991-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-28 | 1994-08-30 | 1995-03-01 | $7700.00 | Window Closed / Lapsed |