Method and apparatus for sample analysis

• US 6,865,926 B2
• Filed: 05/14/2003
• Issued: 03/15/2005
• Est. Priority Date: 01/25/2000
• Status: Expired due to Term

• Current Assignee: State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Portland State University
• Original Assignee: State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Portland State University
• Inventors: O'Brien, Robert J., Smith, Thomas R.
• Primary Examiner(s): CYGAN, MICHAEL T
• Application Number:
  US10/438,517
• Publication Number:
  US 20040035183A1
• Time in Patent Office: 671 Days
• Field of Search: 73/234.2, 73/232.7
• US Class Current: 73/23.27
• CPC Class Codes: G01N 1/2202 involving separation of sample components during sampling
• CPC Class Codes: G01N 1/24 Suction devices G01N1/22 - G01N1/2294 take precedence
• CPC Class Codes: G01N 1/40 Concentrating samples
• CPC Class Codes: G01N 2001/2223 aerosol sampling devices
• CPC Class Codes: G01N 2001/2238 the gas being compressed or pressurized
• CPC Class Codes: G01N 2001/2282 with cooling means
• CPC Class Codes: G01N 2001/4027 evaporation leaving a concentrated sample
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: G01N 2015/0092 Monitoring flocculation or agglomeration
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 2030/207 with metering cavity, e.g. sample loop
• CPC Class Codes: G01N 2030/328 valves, e.g. check valves of pumps
• CPC Class Codes: G01N 2030/625 by measuring reference material, e.g. carrier without sample
• CPC Class Codes: G01N 2030/626 calibration, baseline
• CPC Class Codes: G01N 30/06 Preparation
• CPC Class Codes: G01N 30/08 using an enricher
• CPC Class Codes: G01N 30/22 in high pressure liquid systems
• CPC Class Codes: G01N 30/32 of pressure or speed G01N30/36 takes precedence
• CPC Class Codes: G01N 30/8606 Integration
• CPC Class Codes: G01N 30/8641 Baseline

Abstract

Methods and systems for analyzing samples, such as gas samples, are described. One method comprises providing a gas sample, increasing pressure applied to the gas sample to compress the sample to a smaller volume and provide a pneumatically focused gas sample, and analyzing the pneumatically focused gas sample using any of a variety of analytical techniques. Also disclosed are systems for gas analysis, including systems for analysis of pneumatically focused, and thereby concentrated, gas samples and for analysis of particulate matter in gas samples. Analytical systems constructed within personal computer cases also are disclosed.

Claims

1. A gas chromatograph and gaseous sample analysis system, comprising:

a sample loop for receiving a gaseous sample;

a separatory column fluidly connected to and downstream of the sample loop;

an inline pressure-increasing device which is located downstream of the separatory column and which is configured to increase system pressure to at least 150 psi to pneumatically focus the gaseous sample; and

a detector downstream or upstream of the pressure increasing device for detecting analytes.

2. The system of claim 1 where the inline pressure-increasing device is further configured to reduce linear flow rate to lower than linear flow rate through the system prior to increasing the pressure with the inline device.

3. The system of claim 1 where the inline pressure-increasing device is further configured to increase linear flow rate to higher than linear flow rate through the system prior to increasing the pressure with the inline device.

4. The system of claim 1 where the inline pressure-increasing device is further configured to maintain linear flow rate substantially the same as linear flow rate through the system prior to increasing the pressure with the inline device.

5. The system of claim 1 where the sample loop is of sufficient capacity to provide adequate analyte sensitivity once the sample is pneumatically focused, and wherein the system is further configured to inject all of or a portion of the pneumatically focused sample into the separatory column.

6. The system of claim 1 including plural separatory columns.

7. The system of claim 1 including plural detectors.

8. The system of claim 1 and including a vacuum pump to draw a gas sample through the column.

9. The system of claim 1 and further comprising plural separatory columns.

10. The system of claim 1 and further comprising plural sample collection coils and plural separatory columns.

11. The system of claim 1 and further including a sample collection pump for drawing the gaseous sample into the gas sample loop.

12. The system of claim 1 and further including a computer for controlling the system.

13. The system of claim 12 where the computer is operated by a neural network and expert systems.

14. The system of claim 1 where the gas chromatograph is located on a microchip.

15. The system of claim 12, wherein the system is contained within a computer case.

16. The system of claim 1, wherein the inline pressure increasing device is selected from the group consisting of a calibrated leak, a frit restrictor, a tapered capillary restrictor, a feedback regulator, a needle valve, and a crimped capillary flow regulator.

17. The system of claim 15, wherein the computer case is selected from the group consisting of AT, BATX, ATX, MATX, LPX and microATX compatible cases.

18. The system of claim 15, wherein the computer case is selected from the group consisting of full tower, tower, mid-tower, microtower, desktop, rackmount and server chassis cases.

19. The system of claim 1 where the sample loop is configured to withstand system pressure used to pneumatically focus the sample.

20. The system of claim 19 where the sample loop is configured to withstand pressures from 200 psi to 2,000 psi.

21. The system of claim 1 where the inline pressure-increasing device is configured to increase system pressure to a pressure of 150 psi to 15,000 psi.

22. The system of claim 1 where the inline-pressure-increasing device is configured to increase system pressure to a pressure of 200 psi to 2,000 psi.

23. The system of claim 1 further including a valve configured to direct a carrier gas through the sample loop containing the first volume of the gaseous sample as the inline pressure-increasing device increases system pressure.

24. The system of claim 1 where the inline-pressure increasing device is further configured to decrease system pressure after the gaseous sample is pneumatically focused and injected into the separatory column.

25. The system of claim 23 where system pressure is increased and decreased under computer control.

26. The system of claim 1 where the inline-pressure increasing device comprises a needle valve under computer control.