Systems and methods for conserving carrier gas

Patent metadata

Field	Value
Publication number	US-9874546-B2
Application number	US-201514808657-A
Country	US
Kind code	B2
Filing date	Jul 24, 2015
Priority date	Jul 24, 2015
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

A device for a gas chromatograph system includes an injector, a conduit assembly, a flow restrictor, and a pressure controller. The injector is connected to a carrier gas source and an auxiliary gas source. The conduit assembly surrounds the input end of an analytical column. A carrier gas is supplied at a constant pressure through a flow restrictor to the injector. A pressure controller is configured to control the pressure of an auxiliary gas supplied to the injector from the auxiliary source. The pressure controller is configured to operate in a first mode to provide a first auxiliary gas pressure sufficient to force a flow of the auxiliary gas and a sample onto the analytical column during an inject phase and to operate in a second mode to provide a second auxiliary gas pressure below a threshold necessary to flow auxiliary gas into the analytical column during a resolving phase.

First claim

What is claimed is:

1. A device for a gas chromatograph system comprising:
an injector connected to a carrier gas source and an auxiliary gas source;
a conduit assembly surrounding the input end of an analytical column;
a flow restrictor coupled to the conduit assembly through which a carrier gas is supplied to the injector from the carrier gas source at a constant pressure; and
a pressure controller configured to control the pressure of an auxiliary gas supplied to the injector from the auxiliary source, the pressure controller configured to operate in a first mode to provide a first auxiliary gas pressure sufficient to force a flow of the auxiliary gas and a sample onto the analytical column during an inject phase and to operate in a second mode to provide a second auxiliary gas pressure below a threshold necessary to flow auxiliary gas into the analytical column during a resolving phase.

2. The device of claim 1 , wherein the carrier gas includes He or H 2 .

3. The device of claim 1 , wherein the auxiliary gas includes N 2 or Ar.

4. The device of claim 1 , wherein the flow restrictor is sized to provide a volume of carrier gas sufficient to prevent the auxiliary gas from entering the analytical column when the pressure control is operating in the second mode.

5. The device of claim 1 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of at least about 1.5.

6. The device of claim 5 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of at least about 2.

7. The device of claim 6 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of at least about 4.

8. The device of claim 1 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of not more than about 10.

9. The device of claim 8 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of not more than about 5.

10. The device of claim 1 , wherein the flow restrictor provides a volume of carrier gas between about 1.0 sccm and about 10 sccm.

11. The device of claim 10 , wherein the flow restrictor provides a volume of carrier gas between about 2 sccm and about 5 sccm.

12. The device of claim 1 , wherein the injector is a split/splitless (SSL) injector.

13. The device of claim 1 , wherein the injector is a programmed temperature vaporization (PTV) injector.

14. A gas chromatograph system comprising:
an analytical column;
a detector coupled to an output end of the analytical column;
an injector connected to a carrier gas source and an auxiliary gas source;
a conduit assembly surrounding the input end of an analytical column;
a flow restrictor coupled to the conduit assembly through which a carrier gas is supplied to the injector from the carrier gas source at a substantially constant pressure; and
a pressure controller configured to control the pressure of an auxiliary gas supplied to the injector from the auxiliary source, the pressure controller configured to provide a first auxiliary gas pressure sufficient to force a flow of the auxiliary gas and a sample onto the analytical column during an inject phase and a second auxiliary gas pressure below a threshold necessary to flow auxiliary gas into the analytical column during a resolving phase.

15. The system of claim 14 , wherein the detector is a mass spectrometer.

16. The system of claim 14 , wherein the injector is a split/splitless (SSL) injector.

17. The system of claim 14 , wherein the injector is a programmed temperature vaporization (PTV) injector.

18. The system of claim 14 , wherein the carrier gas includes He or H 2 .

19. The system of claim 14 , wherein the auxiliary gas includes N 2 or Ar.

20. The system of claim 14 , wherein the flow restrictor is sized to provide a volume of carrier gas sufficient to prevent the auxiliary gas from entering the analytical column when the pressure control is operating in the second mode.

21. The system of claim 14 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of at least about 1.5.

22. The system of claim 14 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of not more than about 10.

23. The system of claim 14 , wherein the flow restrictor provides a volume of carrier gas between about 1.0 sccm and about 10 sccm.

24. The method of claim 23 , wherein the flow restrictor provides a volume of carrier gas between about 1.0 sccm and about 10 sccm.

25. A method for supplying a carrier gas to a gas chromatograph, comprising:
providing a carrier gas flow and an auxiliary gas flow to an injector, the carrier gas flow being at a substantially fixed pressure and passing through a flow restrictor;
changing an auxiliary gas pressure during an inject phase to a first pressure sufficient to force at least a portion of the auxiliary gas flow and at least a portion of a sample onto an analytical column;
changing an auxiliary gas pressure during an resolving phase to an operating pressure of the analytical column;
resolving at least two compounds of the sample with the analytical column; and
detecting the at least two compounds exiting the analytical column.

26. The method of claim 25 , wherein the detector is a mass spectrometer.

27. The method of claim 25 , wherein the carrier gas includes He or H 2 .

28. The method of claim 25 , wherein the auxiliary gas includes N 2 , Ar, or H 2 .

29. The method of claim 25 , wherein the flow restrictor is sized to provide a volume of carrier gas sufficient to prevent the auxiliary from entering the analytical column during the resolving phase.

30. The method of claim 25 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of at least about 1.5.

31. The method of claim 25 , wherein the flow restrictor is sized to provide a volume of carrier gas that exceeds the operating flow of the analytical column by a factor of not more than about 10.

Assignees

• Thermo Finnigan Llc

Inventors

• Mccauley Edward B

Classifications

• G01N2030/025

  Gas chromatography · CPC title

• G01N2030/324

  speed, flow rate · CPC title

• G01N30/18 Primary

  using a septum or microsyringe · CPC title

• G01N2030/127

  PTV evaporation · CPC title