Multi-dimensional portable gas chromatograph system

• US 20070266858A1
• Filed: 05/16/2006
• Published: 11/22/2007
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: Ludlum Measurements, Inc.
• Original Assignee: VPI Engineering, Inc.
• Inventors: Maxwell, Derek, Alm, Sheena, Wunner, Ken, Kaspersen, Mark, Lewis, Collin, Blankevoort, John, Bentley, Jim
• Granted Patent: US 7,735,352 B2
• Time in Patent Office: Days
• US Class Current: 96/105
• CPC Class Codes: G01N 2030/0095 Separation specially adapted for use outside laboratory, e.g. field sampling, portable equipments
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 2030/625 by measuring reference material, e.g. carrier without sample
• CPC Class Codes: G01N 30/463 for multidimensional chromatography
• CPC Class Codes: G01N 30/66 Thermal conductivity detectors

Abstract

A portable multi-dimensional gas chromatograph, the gas chromatograph including a carrier gas container, a regulator fluidly connected to the carrier gas container, a dopant chamber containing a reference chemical, at least one pre-concentrator which is fluidly connected to the regulator and the dopant chamber, a first separation column fluidly connected to the at least one pre-concentrator, a second separation column fluidly connected to the at least one pre-concentrator, a first detector fluidly connected to the first separation column, and a second detector fluidly connected to the second separation column.

Claims

1. A portable multi-dimensional gas chromatograph, the gas chromatograph comprising:

a carrier gas container;

a regulator fluidly connected to the carrier gas container;

a dopant chamber containing a reference chemical;

at least one pre-concentrator which is fluidly connected to the regulator and the dopant chamber;

a first separation column fluidly connected to the at least one pre-concentrator;

a second separation column fluidly connected to the at least one pre-concentrator;

a first detector fluidly connected to the first separation column, and

a second detector fluidly connected to the second separation column.

2. The portable multi-dimensional gas chromatograph of claim 1 wherein each of said first separation column and said second separation column has a length of at least about 15 meters.

3. The portable multi-dimensional gas chromatograph of claim 1 wherein at least one of said at least two columns comprises polydimethylsiloxane.

4. The portable multi-dimensional gas chromatograph of claim 1 wherein at least one of said at least two columns comprises polyethylene glycol.

5. The portable multi-dimensional gas chromatograph of claim 1 wherein said at least one reference chemical is 1,4-dichlorobenzene.

6. The portable multi-dimensional gas chromatograph of claim 1 wherein said first detector and said second detector are selected from the group consisting of photoionization, atomic emission, chemiluminescence, electron-capture, flame ionization, mass spectrometer, thermal conductivity, flame photometric, infrared, Fourier Transform infrared, ultraviolet/visible absorbance, far ultraviolet absorbence, and nitrogen phosphorous.

7. The portable multi-dimensional gas chromatograph of claim 1 wherein said first detector, at least one second detector, or both are thermal conductivity detectors.

8. The portable multi-dimensional gas chromatograph of claim 1 wherein said first detector, said second detector, or both, have the sensitivity to measure chemicals at a concentration of parts per one hundred million to parts-per-billion.

9. The portable multi-dimensional gas chromatograph of claim 1 wherein said at least one pre-concentrator is a graphitized carbon-based molecular sieve.

10. The portable multi-dimensional gas chromatograph of claim 1 further comprising a first heater with heater control electronics in contact with said first separation column.

11. The portable multi-dimensional gas chromatograph of claim 1 comprising a second heater with heater control electronics, said second heater in contact with said second separation column.

12. The portable multi-dimensional gas chromatograph of claim 1 wherein said portable gas chromatograph further comprises a heater with heater control electronics in contact with said at least one pre-concentrator.

13. The portable multi-dimensional gas chromatograph of claim 1 wherein said first detector has a first output signal and said second detector has a second output signal, said first output signal and said second output signal in communication with a signal processing unit.

14. The portable multi-dimensional gas chromatograph of claim 13 wherein said signal processing unit further comprises analog signal processing electronics in communication with said first detector, said second detector or both.

15. The portable multi-dimensional gas chromatograph of claim 13 wherein said signal processing unit further comprises digital signal processing electronics in communication with said analog signal processing electronics.

16. The portable multi-dimensional gas chromatograph of claim 13 wherein signal processing unit further includes a central processing unit.

17. The portable multi-dimensional gas chromatograph of claim 13 wherein said signal processing unit further includes a recognition library.

18. The portable multi-dimensional gas chromatograph of claim 14 wherein said signal processing unit is further in communication with a wireless radio which allows wireless communication between the central processing unit and an external computer.

19. The portable multi-dimensional gas chromatograph of claim 17 wherein said central processing unit is in communication with a display.

20. A portable multi-dimensional gas chromatograph, the gas chromatograph comprising:

a carrier gas container;

a regulator fluidly connected to the carrier gas container;

a dopant chamber containing a reference chemical;

at least one pre-concentrator which is fluidly connected to the regulator and the dopant chamber;

a first chromatograph column assembly fluidly connected to the at least one pre-concentrator, the column assembly comprising a first housing, the first housing defining a first chamber, a column support, wherein the column support is ring-shaped about an axis and comprises a circumferential outer surface oriented about the axis and a plurality of axially oriented bridges, the bridges extending radially from the outer surface of the column support, and wherein the column support is positioned within the first chamber;

and column tubing wound around the column support, wherein the column tubing is in contact with the plurality of bridges and is separated from the outer surface of the column support;

a second chromatograph column assembly fluidly connected to the at least one pre-concentrator;

a first detector fluidly connected to the first separation column, and a second detector fluidly connected to the second separation column.

21. The portable multi-dimensional gas chromatograph of claim 20 wherein said second chromatograph column assembly is the same as the first chromatograph column assembly.

22. A portable multi-dimensional gas chromatograph, the gas chromatograph comprising:

a carrier gas container;

a regulator fluidly connected to the carrier gas container;

a dopant chamber containing a reference chemical;

at least one pre-concentrator which is fluidly connected to the regulator and the dopant chamber;

a separation column fluidly connected to the at least one pre-concentrator; and

a thermal conductivity detector fluidly connected to the first separation column;

wherein the thermal conductivity detector comprises;

a housing having an internal gas analysis chamber, a fluid inlet passageway in communication with the gas analysis chamber, a fluid outlet passageway in communication with the gas analysis chamber, and a first bore extending through at least a portion of the housing, the first bore in fluid communication with the gas analysis chamber, the first bore offset from the fluid inlet passageway and the fluid outlet passageway;

a thermistor having an electrical lead; and

a first contact pin electrically connected to said electrical lead;

wherein the first contact pin is oriented within the first bore, and the first contact pin is electrically insulated from the housing and mechanically secured to the housing.

23. The portable multi-dimensional gas chromatograph of claim 22, the thermal conductivity detector further comprising a second contact pin, the housing further comprising a second bore in fluid communication with the gas analysis chamber, the thermistor further comprising a second electrical lead electrically connected to the second contact pin, wherein the second contact pin is oriented within the second bore, and the second contact pin is electrically insulated from the housing and mechanically secured to the housing.

24. A portable multi-dimensional gas chromatograph, the gas chromatograph comprising:

a carrier gas container;

a regulator fluidly connected to the carrier gas container, wherein the regulator has at least two ports, one being a gas input port and one being a gas output port and a gas flow path between and in fluid communication with the at least two ports, the gas flow path comprising two or more pressure reducing gas stages each stage having two ends, one being a first end and one being a second end;

wherein at least two of the at least two stages are positioned along substantially parallel axis and have their two ends oriented in substantially opposite directions;

a dopant chamber containing a reference chemical;

at least one pre-concentrator which is fluidly connected to the regulator and the dopant chamber;

a first separation column fluidly connected to the at least one pre-concentrator;

a second separation column fluidly connected to the at least one pre-concentrator;

a first detector fluidly connected to the first separation column, and

a second detector fluidly connected to the second separation column.

25. The portable multi-dimensional gas chromatograph of claim 24, further comprising:

a C-10 adaptor connecting the carrier gas container;

the regulator further comprising;

a first stage capable of reducing gas pressure from approximately 2000 psi to approximately 200 psi, the first stage engaged to the C-10 adaptor;

a transfer conduit connecting the first stage to a 10 micron frit;

the 10 micron frit engaged to a second stage capable of reducing the gas pressure from approximately 200 psi to 40 psi +/−

1 psi;

a shut off assembly engaged to the second stage; and

a two port output defining the terminus from which gas can exit the device at a constant 40 psi +/−

1 psi pressure;

the first and second stages being oriented along substantially parallel axis and being substantially oppositely oriented,

the device having dimensions of a length of 4.64 inches, a width of 1.25 inches and a height of 2.75.