Silicon micro-machined fixed-volume back-flush injector having no unswept dead volume during injection

• US 20020178785A1
• Filed: 06/01/2001
• Published: 12/05/2002
• Est. Priority Date: 06/01/2001
• Status: Active Grant

• Current Assignee: INFICON GmbH (Inficon Holding AG)
• Original Assignee: Chi K. Lo, Tak K. Wang
• Inventors: Wang, Tak K., Lo, Chi K.
• Granted Patent: US 6,575,014 B2
• Time in Patent Office: Days
• US Class Current: 73/23.41
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2001/387 mixing by blowing a gas, bubbling
• CPC Class Codes: G01N 2035/00247 Microvalves
• CPC Class Codes: G01N 2035/1044 Using pneumatic means
• CPC Class Codes: G01N 30/16 Injection G01N30/24 takes precedence
• CPC Class Codes: G01N 30/40 using back flushing
• CPC Class Codes: G01N 30/6095 Micromachined or nanomachined, e.g. micro- or nanosize

Abstract

A micro-machined back-flush injector that allows for a sample introduced into the injector to be properly injected into a gas chromatography apparatus in a short time period of between 10 and 100 milliseconds. A micro-machined injector having back-flushing capability that allows back-purging of unwanted components in the device and provides clean-up of channels in contact with the sample. Further, a method of operating an injector such that a sample is properly injected and purged from the system to which the injector is operably attached.

Claims

1. A micro-machined back-flush injector comprising:

a sample inlet;

an analytical column inlet channel; and

a plurality of channels that connect the sample inlet and the analytical column inlet channel, wherein the plurality of channels include a fixed sample loop connecting a sample valve and a fore-flush valve in the injector.

2. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

an inlet channel connecting the sample inlet and the sample valve.

3. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

a pre-column inlet channel connecting an injection valve and a pre-column.

4. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

a dead volume channel connecting the sample valve and an injection valve.

5. The micro-machined back-flush injector of claim 4, wherein the dead volume channel comprises a channel along the shortest available path length between the sample valve and an injection valve.

6. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

a main carrier gas loop connecting the fore-flush valve and a carrier gas inlet.

7. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

a pre-column back-flush loop connecting a main carrier gas loop and a back-flush valve.

8. The micro-machined back-flush injector of claim 1, wherein the analytical column inlet channel connects a back-flush valve and an analytical column.

9. The micro-machined back-flush injector of claim 1, wherein the plurality of channels further comprise:

a pre-column outlet channel connecting a back-flush valve and a pre-column.

10. A method of operating a back-flush injector comprising:

introducing a sample into the injector;

injecting the sample into an analytical device; and

purging substantially all of the sample from the injector.

11. The method of claim 10, wherein the introducing step comprises:

allowing the sample to fill an inlet channel, a dead volume channel, a fixed sample loop and a sample chamber of the injector.

12. The method of claim 10, wherein the introducing step comprises:

filling a main carrier gas loop, a reference column back-flush loop, a pre-column back-flush loop and an analytical column inlet channel of the injector with carrier gas.

13. The method of claim 10, wherein the introducing step comprises opening a vacuum pump and subsequently opening a sampling valve.

14. The method of claim 10, further comprising compressing the sample.

15. The method of claim 14, wherein the compressing step comprises allowing carrier gas to flow into a sample chamber of the injector.

16. The method of claim 14, wherein the compressing step comprises compressing the sample into a sample chamber, a fixed sample loop and a dead volume channel.

17. The method of claim 10, wherein the injecting step further comprises allowing a carrier gas to push the sample through a dead volume channel.

18. The method of claim 10, wherein the injecting step comprises allowing the sample to flow into a pre-column inlet channel of the injector.

19. The method of claim 10, wherein the back-flushing step comprises allowing carrier gas to flow into a fixed sample loop, a dead volume channel and a pre-column inlet channel of the injector.

20. The method of claim 10, wherein the back-flushing step comprises allowing carrier gas to displace any sample in a pre-column.