Method and apparatus for sample analysis

• US 7,621,171 B2
• Filed: 03/06/2007
• Issued: 11/24/2009
• 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
• Primary Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US11/715,273
• Publication Number:
  US 20070271997A1
• Time in Patent Office: 994 Days
• Field of Search: 73/234.2, 73/234.1, 73/232.2, 73/232.7, 73/233.5
• US Class Current: 73/23.41
• CPC Class Codes: G01N 1/2202 involving separation of sample components during sampling
• CPC Class Codes: G01N 1/40 Concentrating samples
• CPC Class Codes: G01N 1/405 by adsorption or absorption
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 2030/324 speed, flow rate
• CPC Class Codes: G01N 2030/685 flame photometry
• CPC Class Codes: G01N 21/3518 Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques
• CPC Class Codes: G01N 21/51 inside a container, e.g. in an ampoule G01N21/53 takes precedence
• CPC Class Codes: G01N 30/32 of pressure or speed G01N30/36 takes precedence

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 method for analyzing a gas sample, comprising:

providing a gas sample or converting a sample to a gas sample;

concurrently with or prior to delivery of the gas to a spectrometric cell, increasing pressure applied to the gas sample to compress the sample to a smaller volume and provide a pneumatically focused gas sample at a pressure of from 150 psi to 2,000 psi; and

analyzing the pneumatically focused gas sample at a pressure of from 150 psi to 2,000 psi in a spectrometric cell by light spectroscopy.

2. The method of claim 1 wherein the gas sample is pneumatically focused concurrently with or just prior to reaching a spectrometric cell.

3. The method of claim 1 wherein providing a gas sample comprises continuously providing an air sample for pollution analysis.

4. The method of claim 1 wherein the sample is analyzed using an optical waveguide.

5. The method of claim 1 wherein methane in the sample is used as an internal standard.

6. The method of claim 1 further comprising continuously analyzing pneumatically focused samples.

7. The method of claim 1 wherein analytes from the pneumatically focused sample are determined by a detector selected from the group consisting of IR, FTIR, NDIR, ECD, TCD, NPD, FPD, UV/Visible detectors, and combinations thereof.

8. The method of claim 1 wherein the gas sample is an exhalation from a respiratory organism.

9. The method of claim 1 further comprising removing materials from the gaseous sample prior to pneumatically focusing the sample.

10. The method of claim 9 wherein materials removed from the sample are selected from the group consisting of water vapor, aerosols, ozone, NO₂, and combinations thereof.

11. The method of claim 9 wherein the materials are removed by filtering, absorption, vortexing, and combinations or a combination thereof.

12. The method of claim 1 wherein the air sample contains water vapor, the method further comprising condensing water vapor in the gaseous air sample by the increasing of pressure applied to the gas sample.

13. The method of claim 12 wherein the condensed water vapor is removed prior to analyzing the gaseous air sample in the spectrometric cell by light spectroscopy.

14. The method of claim 13 wherein the condensed water vapor contains water-soluble analytes, and such water-soluble analytes are collected for continuous or discontinuous subsequent analysis.

15. The method of claim 1 wherein the pneumatically focused sample is separated into aqueous and gaseous components which are separately analyzed.

16. The method of claim 1 wherein the pneumatically focused sample is subsequently cryogenically liquefied.

17. The method of claim 1 wherein the analyzing comprises analyzing the pneumatically focused gas sample for the presence of benzene.

18. A method for analyzing an air sample, comprising:

collecting an air sample;

concurrently with or prior to delivery of the air sample to a spectrometric cell, increasing the pressure of the sample to a pressure of from 150 psi to 2,000 psi to pneumatically focus the air sample; and

analyzing the pneumatically focused sample in real time at a pressure of from 150 psi to 2,000 psi in a spectrometric cell using a light spectrometer.

19. The method of claim 18 and further including cryofocusing the air sample either prior to or subsequent to pneumatically focusing the sample.

20. The method of claim 18 wherein the analyzing comprises analyzing the pneumatically focused air sample for the presence of benzene.