Liquid Chromatography Detector and Flow Controller Therefor

• US 20110083493A1
• Filed: 06/11/2009
• Published: 04/14/2011
• Est. Priority Date: 06/11/2008
• Status: Abandoned Application

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Xu, Zhi
• Application Number:
  US12/997,182
• Publication Number:
  US 20110083493A1
• Time in Patent Office: Days
• US Class Current: 73/61.56
• CPC Class Codes: G01N 2030/847 by pneumatic means
• CPC Class Codes: G01N 2030/8494 Desolvation chambers
• CPC Class Codes: G01N 30/74 Optical detectors measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J
• CPC Class Codes: G01N 30/84 Preparation of the fraction to be distributed

Abstract

A flow controller for use with a liquid chromatography detector. The flow controller includes a flow channel comprising an inlet portion, a control channel portion in communication with the inlet portion, and an outlet portion in communication with said control channel portion. The control channel portion has a cross-sectional area smaller than a cross-sectional area of a drift tube of the liquid chromatography detector for channeling the flow of droplets through the smaller cross-sectional area. The flow controller is shaped and sized to reduce pressure fluctuations and turbulence in the droplet stream of the liquid chromatography detector.

Claims

1. A liquid chromatography detector comprising:

a nebulizer producing droplets for analysis;

a detection cell adapted for receiving the droplets produced by the nebulizer for analysis by the detection cell;

a drift tube arranged between the nebulizer and the detection cell adapted for guiding the droplets from the nebulizer to the detection cell as a droplet stream through the drift tube; and

a flow controller arranged in the nebulizer and in communication with the drift tube for transmitting the droplet stream from the nebulizer, said flow controller comprising a flow channel with a flow channel inlet and a flow channel outlet, wherein the diameter of the flow channel inlet is greater than the diameter of the flow channel outlet.

2. A liquid chromatography detector as set forth in claim 1 wherein the flow controller includes a control channel portion between the flow channel inlet and the flow channel outlet, said control channel portion having a cross-sectional area that is smaller than the cross-sectional area of the drift tube.

3. A liquid chromatography detector as set forth in claim 2 wherein the flow channel inlet comprises a tapered inlet sidewall extending from an open mouth of the flow controller and narrowing to the size and shape of the cross-section of the control channel portion.

4. A liquid chromatography detector as set forth in claim 3 wherein said tapered inlet sidewall extends at an angle α

measured between opposite sides of the tapered inlet sidewall, said angle α

being about 25 degrees.

5. A liquid chromatography detector as set forth in claim 1 wherein the flow controller includes a control channel portion between the flow channel inlet and the flow channel outlet, said flow channel outlet having a diameter that is substantially the same as the diameter control channel portion.

6. A liquid chromatography detector as set forth in claim 1 wherein the flow channel outlet diameter is between about 0.125 inches and 0.1875 inches.

7. A liquid chromatography detector as set forth in claim 6 wherein the flow channel inlet diameter is between about 0.85 inches.

8. A liquid chromatography detector as set forth in claim 1 further comprising another flow controller arranged between the nebulizer and the detection cell and in communication with the drift tube for receiving the droplet stream, said other flow controller comprising a flow channel having a cross-sectional area smaller than a cross-sectional area of the drift tube for channeling the flow of the droplet stream through the smaller cross-sectional area, said flow controllers being shaped and sized to reduce turbulence in the droplet stream received by the detection cell.

9. A liquid chromatography detector as set forth in claim 1 further comprising another flow controller arranged between the nebulizer and the detection cell and in communication with the drift tube for receiving the droplet stream, said other flow controller comprising a flow channel with a flow channel inlet and a flow channel outlet, said flow channel inlet having a diameter greater than that of the flow channel outlet, said flow controllers being shaped and sized to reduce turbulence in the droplet stream received by the detection cell.

10. A liquid chromatography detector as set forth in claim 9 wherein the flow controller comprises a first flow controller and the other flow controller comprises a second flow controller, and further comprising a third flow controller arranged between the first and second flow controllers and in communication with the first and second flow controllers.

11. A flow controller for use with a liquid chromatography detector comprising a nebulizer producing droplets for analysis, a detector adapted for analyzing the droplets, a drift tube shaped and sized for guiding the droplets from the nebulizer to the detector, said drift tube having a cross-sectional area, said flow controller comprising:

a flow channel comprising,

an inlet portion having an inlet diameter;

a control channel portion in communication with said inlet portion; and

an outlet portion in communication with said control channel portion, said outlet portion having diameter that is smaller than the inlet diameter.

12. A liquid chromatography detector as set forth in claim 11 wherein the control channel portion has a diameter, said control channel diameter being substantially the same as the outlet diameter.

13. A liquid chromatography detector as set forth in claim 11 wherein the control channel portion has a diameter, and the control channel diameter and the outlet diameter are each between about 0.125 inches and 0.1875 inches.

14. A liquid chromatography detector as set forth in claim 11 wherein the flow channel has a length of about 2.25 inches.

15. A liquid chromatography detector comprising:

a nebulizer producing droplets for analysis;

a detection cell adapted for receiving the droplets produced by the nebulizer for analysis by the detection cell;

a drift tube arranged between the nebulizer and the detection cell adapted for guiding the droplets from the nebulizer to the detection cell as a droplet stream through the drift tube; and

a flow controller arranged between the nebulizer and the detection cell and in communication with the drift tube for receiving the droplet stream, said flow controller comprising a flow channel with a flow channel inlet and a flow channel outlet, wherein the flow channel outlet has a diameter and the flow channel inlet has a diameter, said flow channel outlet diameter being smaller than said flow channel inlet diameter and being in communication with the detection cell.

16. A liquid chromatography detector as set forth in claim 15 wherein the flow controller includes a control channel portion between the flow channel inlet and the flow channel outlet for channeling the flow of the droplet stream, said control channel portion having a cross-sectional area that is smaller than the cross-sectional area of the drift tube.

17. A liquid chromatography detector as set forth in claim 16 wherein the flow channel inlet comprises a tapered inlet sidewall extending from an open mouth of the flow controller and narrowing to the size and shape of the cross-section of the control channel portion.

18. A liquid chromatography detector as set forth in claim 17 wherein said tapered inlet sidewall extends at an angle α

measured between opposite sides of the tapered inlet sidewall, said angle α

being about 5 degrees.

19. A liquid chromatography detector as set forth in claim 15 wherein the flow controller includes a control channel portion between the flow channel inlet and the flow channel outlet for channeling the flow of the droplet stream, said control channel portion having a diameter that is substantially the same as the diameter of the flow channel outlet.

20. A liquid chromatography detector as set forth in claim 15 wherein the flow channel outlet diameter is between about 0.125 inches and 0.1875 inches.

21. A liquid chromatography detector as set forth in claim 20 wherein the flow channel inlet diameter is between about 0.85 inches.

22. A liquid chromatography detector as set forth in claim 15 further comprising another flow controller arranged in the nebulizer and in communication with the drift tube for transmitting the droplet stream, said other flow controller comprising a flow channel having a cross-sectional area smaller than a cross-sectional area of the drift tube for channeling the flow of the droplet stream through the smaller cross-sectional area, said flow controllers being shaped and sized to reduce turbulence in the droplet stream received by the detection cell.