US 5,522,988 AGranted

On-line coupled liquid and gas chromatography system with an interface capillary tube interposed between a pair of capillary chromatographic columns

AssigneeThe Dow Chemical Company

InventorsHernan J. Cortes, Curtis D. Pfeiffer, Bruce E. Richter

Life of this patent

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Abstract

Apparatus and method for on-line coupled liquid chromatography and gas chromatography analysis. The system includes a high-volume, liquid vaporizing chamber, or interface capillary tube which allows injection of a substantial volume of sample-carrying eluent and concentrates bands, obviating adverse effects on the resolution or peak shape of the components of interest. The vaporizing chamber is interposed between a packed or wall-coated open tubular capillary liquid chromatographic column and a capillary gas chromatographic column. The capillary liquid chromatographic column permits the use of small volumes of eluent and reduced flow rates.

Claims4

Dependent claims

Apparatus for introducing sample sequentially into a liquid chromatography capillary column means and a gas chromatography capillary column means, the apparatus comprising in cooperative combination:

(a) a liquid chromatography capillary column means,
(b) a valve means for adding sample to the liquid chromatography capillary column means and a liquid chromatography pump means for adding liquid eluent to the liquid chromatography capillary column means whereby the sample is eluted through the liquid chromatography capillary column means and separated into components dispersed in the liquid effluent of the liquid chromatography capillary column means,
(c) a gas chromatography capillary column means comprising a gas chromatography column having a stationary phase which is directly connected to a section of capillary material free of stationaty phase,
(d) a liquid conduit means communicating between the liquid chromatography capillary column means and the section of capillary material free of stationary phase for adding liquid effluent containing sample originally added to the liquid chromatography column means to the gas chromatography capillary column means,
(e) means for adding a gas to the section of capillary material free of stationary phase,
(f) means for controllably heating the section of capillary material free of stationary phase, and
(g) valving means for starting and stopping the flow of liquid effluent from the liquid chromatography capillary column means to the section of capillary material free of stationary phase and for starting and stopping the flow of gas to the inlet of the gas chromatography capillary columnb means such that when said valving means is stopping the flow of liquid effluent from the liquid capillary column means, said valving means is allowing the addition of gas to the section of capillary material free of stationary phase.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/318,481Filed 5 Oct 1994 · continuation
Priority: 25 Jan 1985
Granted: 4 Jun 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01N 30/465
With serial coupling of separation columns: with specially adapted interfaces between the columns
G01N 30/462
With serial coupling of separation columns: with different eluents or with eluents in different states
G01N 2030/025
Characterised by the kind of separation mechanism: gas chromatography
G01N 2030/165
Injection: retention gaps

Family

Serial695,038Parent of this continuation-in-part · filed 25 Jan 1985
Serial810,798Parent of this continuation · filed 18 Dec 1985
Serial902,911Parent of this continuation · filed 29 Aug 1986
Serial209,609Parent of this continuation · filed 21 Jun 1988
Serial348,354Parent of this continuation · filed 5 May 1989
Serial457,203Parent of this continuation · filed 26 Dec 1989
Serial576,533Parent of this continuation · filed 31 Aug 1990
Serial982,266Parent of this division · filed 25 Nov 1992
Serial68,481Parent of this continuation · filed 28 May 1993
US 5,236,593 AParent of this division
US 5,522,988 AThis patent

From the US filing history. Foreign family members aren’t listed.