PRESSURIZING SAMPLE LOOP BY SAMPLE METERING DEVICE

• US 20120132013A1
• Filed: 06/03/2009
• Published: 05/31/2012
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Glatz, Bernd, Kretz, Wolfgang
• Granted Patent: US 9,435,773 B2
• Time in Patent Office: Days
• US Class Current: 73/863.02
• CPC Class Codes: G01N 2030/027 Liquid chromatography
• CPC Class Codes: G01N 2030/207 with metering cavity, e.g. sample loop
• CPC Class Codes: G01N 30/20 using a sampling valve
• CPC Class Codes: G01N 30/32 of pressure or speed G01N30/36 takes precedence
• CPC Class Codes: G01N 30/36 in high pressure liquid systems

Abstract

A sample injector (200) for use in a fluid separation system (10) for separating compounds of a fluidic sample in a mobile phase, the sample injector (200) comprising a switchable valve (202), a sample loop (204) in fluid communication with the valve (202) and configured for receiving the fluidic sample, a metering device (206) in fluid communication with the sample loop (204) and configured for introducing a metered amount of the fluidic sample on the sample loop (204), and a control unit (208) configured for controlling switching of the valve (202) to transfer the sample loop (204) between a low pressure state and a high pressure state via an intermediate state and for controlling the metering device (206) during the intermediate state to at least partially equilibrate a pressure difference in the sample loop (204) between the low pressure state and the high pressure state.

Claims

1. A sample injector for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the sample injector comprising:

a switchable valve;

a sample loop in fluid communication with the valve and configured for receiving the fluidic sample;

a metering device in fluid communication with the sample loop and configured for introducing a metered amount of the fluidic sample on the sample loop;

a control unit configured for controlling switching of the valve to transfer the sample loop between a low pressure state and a high pressure state via an intermediate state, and for controlling the metering device during the intermediate state to at least partially equilibrate a pressure difference in the sample loop between the low pressure state and the high pressure state.

2. The sample injector of claim 1,

wherein the control unit is configured for controlling switching of the valve to transfer the sample loop from the high pressure state to the low pressure state via the intermediate state and for controlling the metering device during the intermediate state to perform a decompression in the sample loop before transferring the sample loop to the low pressure state.

3. The sample injector of claim 2,

wherein the control unit is configured for controlling the metering device for performing the decompression by retracting a metering piston.

4. The sample injector of claim 1, wherein the control unit is configured for controlling switching of the valve to transfer the sample loop from the low pressure state to the high pressure state via the intermediate state and for controlling the metering device during the intermediate state to perform a precompression in the sample loop before transferring the sample loop to the high pressure state.

5. The sample injector of claim 4,

wherein the control unit is configured for controlling the metering device for performing the precompression by pushing forward a metering piston.

6. The sample injector of claim 1

wherein the metering device is configured as a high pressure metering device.

7. The sample injector of claim 1,

wherein the metering device is configured for providing a pressure of at least 10 MPa, particularly for providing a pressure of at least 50 MPa, more particularly for providing a pressure of at least 100 MPa.

8. The sample injector of claim 1,

wherein the metering device is configured for providing the same pressure as a mobile phase drive, particularly a pumping system, adapted to drive the mobile phase through a separation column of the fluid separation system.

9. The sample injector of claim 1,

wherein the metering device is configured for increasing a pressure in the sample loop, before switching the sample loop from the low pressure state to the high pressure state, to a system pressure of a mobile phase drive, particularly a pumping system, adapted to drive the mobile phase through a separation column of the fluid separation system.

10. The sample injector of claim 1,

wherein the valve comprises a first valve member and a second valve member, wherein at least one of the first and second valve members is adapted to be moved with respect to the other, one of the first and second valve members comprises a plurality of ports, and the other comprises at least one groove for fluidly coupling respective ones of the ports in dependency on a relative movement position of the first and second valve members with respect to each other.

11. The sample injector of claim 10,

wherein the plurality of ports and the at least one groove are designed so that in the intermediate state of the sample loop succeeding the low pressure state and preceding the high pressure state of the sample loop, a pumping system adapted to drive the mobile phase through a separation column is still in fluid communication with the separation column, and the sample loop is no longer at an atmospheric pressure and not yet in fluid communication with the separation column.

12. The sample injector of claim 10,

wherein the plurality of ports and the at least one groove are designed so that in the intermediate state of the sample loop succeeding the high pressure state and preceding the low pressure state of the sample loop, a pumping system adapted to drive the mobile phase through a separation column is still in fluid communication with the separation column, and the sample loop is no longer at a pressure of the pumping system and not yet at an atmospheric pressure.

13. The sample injector of claim 10,

wherein the plurality of ports and the at least one groove are designed so that in the high pressure state of the sample loop, the sample loop is in fluid communication with a pumping system adapted to drive the mobile phase through a separation column and is in fluid communication with the separation column.

14. The sample injector of claim 10,

wherein the plurality of ports and the at least one groove are designed so that in the low pressure state of the sample loop, the sample loop is not in fluid communication with a pumping system adapted to drive the mobile phase through a separation column and is not in fluid communication with the separation column.

15. The sample injector of claim 10,

wherein the plurality of ports and the at least one groove are designed so that a first position of one of the at least one groove is aligned with one of the plurality of ports in the low pressure state of the sample loop, a second position of the one of the at least one groove is aligned with the one of the plurality of ports in the high pressure state of the sample loop, and a third position of the one of the at least one groove is aligned with the one of the plurality of ports in the intermediate state of the sample loop.

16. The sample injector of claim 15,

wherein a stop position of the one of the plurality of ports is defined at the third portion of the one of the at least one groove.

37. The sample injector of claim 1,

wherein the control unit is configured for controlling switching of the valve so that a fluidic path in which both the metering device and the sample loop are arranged is selectively brought in or out of fluid communication with a mobile phase drive, particularly a pumping system, adapted to drive the mobile phase through a separation column of the fluid separation system.

39. A fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid separation system comprising:

a mobile phase drive, particularly a pumping system, adapted to drive the mobile phase through the fluid separation system;

a separation unit, particularly a chromatographic column, adapted for separating compounds of the fluidic sample in the mobile phase;

a sample injector of claim 1 for introducing the fluidic sample into the mobile phase.

17. (canceled)

18. The sample injector of claim 1,

comprising a pressure sensor arranged for measuring a pressure in the sample loop and for providing the measured pressure to the control unit as a basis for the controlling of at least one of the metering device and the valve.

18-1. (canceled)

19-36. -36. (canceled)

40. (canceled)

41. A method of operating a sample injector in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the method comprising:

introducing, by a metering device, a metered amount of the fluidic sample on a sample loop in fluid communication with a switchable valve and with the metering device;

controlling switching of the valve to transfer the sample loop between a low pressure state and a high pressure state via an intermediate state; and

controlling the metering device during the intermediate state to at least partially equilibrate a pressure difference in the sample loop between the low pressure state and the high pressure state.