US4151741A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for gas chromatographic analysis
Assignee: Bayer AG
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Filing: 1977-07-11
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Granted: 1979-05-01
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Expires: 1997-07-11
Abstract
Abstract An improvement in the resolution, sensitivity of measurement and sensitivity of detection in gas chromatographic analysis using a capillary column or micropacked column as a separating column and a thermal conductivity cell as a detector wherein the pressure in the gas chamber at the beginning of the separating column is higher than in the detector by a factor of at least 5.
Inventors
- 👤 Horst Schirrmeister
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:43
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/26; G01N30/28; G01N30/32; G01N30/62; G01N30/64; G01N30/66
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
71 words
In a method of gas chromatographic analysis wherein the improvement comprises providing a separating column comprising one of a capillary column or micropacked column and a detector comprising a thermal conductivity cell, and maintaining the absolute pressure of the gas immediately upstream of the separating column higher than that in the detector by a factor of at least five by providing a constriction after the separating column and before the detector.
Claim 2
Dependent Claim
71 words
In a method of gas chromatographic analysis wherein the improvement comprises providing a separating column comprising one of a capillary column or micropacked column and a detector comprising a thermal conductivity cell, and maintaining the absolute pressure of the gas immediately upstream of the separating column higher than that in the detector by a factor of at least five by providing a constriction after the separating column and before the detector.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1, further comprising maintaining the pressure of the gas at the outlet of the separating column substantially constant.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 2, wherein the pressure of the gas at the outlet of the separating column is substantially atmospheric pressure.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 1, further comprising removing gas from the thermal conductivity cell by a vacuum pump and providing a constriction between the vacuum pump and the thermal conductivity cell.
Claim 6
Dependent Claim
49 words
A method as claimed in claim 4, wherein an absolute pressure of from 0.5 to 200 mbar is maintained in the thermal conductivity cell by the constrictions arranged before and after the thermal conductivity cell and the pressure at the outlet of the separating column is substantially atmospheric pressure.
Claim 7
Independent Claim
73 words
An apparatus for gas chromatographic analysis, comprising a separating column comprising one of a capillary column or micropacked column, a detector comprising a thermal conductivity cell and means for maintaining the absolute pressure of the gas in the detector lower by a factor of at least five than the absolute pressure of the gas at the outlet of the separating column, comprising a constriction disposed after the separating column and before the detector.
Claim 8
Independent Claim
73 words
An apparatus for gas chromatographic analysis, comprising a separating column comprising one of a capillary column or micropacked column, a detector comprising a thermal conductivity cell and means for maintaining the absolute pressure of the gas in the detector lower by a factor of at least five than the absolute pressure of the gas at the outlet of the separating column, comprising a constriction disposed after the separating column and before the detector.
Claim 9
Dependent Claim
36 words
An apparatus as claimed in claim 6, further comprising regulating means in communication between the constricton and the separating column to maintain the pressure of the gas at the outlet of the separating column substantially constant.
Claim 10
Dependent Claim
22 words
An apparatus as claimed in claim 7, further comprising a vacuum pump connected to the thermal conductivity cell via a further constriction.
Claim 11
Dependent Claim
16 words
An apparatus according to claim 7, wherein the regulating means comprises a communication to atmospheric pressure.
Claim 12
Dependent Claim
53 words
The apparatus according to claim 7, wherein the regulating means maintains the outlet pressure of the separating column at substantially atmospheric pressure, and comprises a tee-connector disposed between the column and the constriction and having a connection to the atmosphere and wherein the detector maintains a pressure of from 0.5 to 200 mbar.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-30 | 1982-10-30 | 1983-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-30 | 1986-10-30 | 1987-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-30 | 1990-10-30 | 1991-05-01 | $7700.00 | Window Closed / Lapsed |