Strobe desorption method for high boiling point materials

• US 7,299,679 B2
• Filed: 03/14/2005
• Issued: 11/27/2007
• Est. Priority Date: 11/21/2002
• Status: Expired due to Fees

• Current Assignee: ADA Technologies, Inc.
• Original Assignee: ADA Technologies, Inc.
• Inventors: Lovell, John Stanley, French, Patrick D., Barringer, Anthony René
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): Rogers; David A.
• Application Number:
  US11/081,006
• Publication Number:
  US 20050235739A1
• Time in Patent Office: 988 Days
• Field of Search: 73 232- 3107, 738/631.1, 738/632.1, 738/635.1, 738/637.1, 738/648.1, 738/648.4
• US Class Current: 73/31.05
• CPC Class Codes: F41H 11/134 Chemical systems, e.g. with detection by vapour analysis
• CPC Class Codes: G01N 1/2202 involving separation of sample components during sampling
• CPC Class Codes: G01N 1/2294 Sampling soil gases or the like
• CPC Class Codes: G01N 1/24 Suction devices G01N1/22 - G01N1/2294 take precedence
• CPC Class Codes: G01N 1/44 Sample treatment involving radiation, e.g. heat
• CPC Class Codes: G01N 2001/2223 aerosol sampling devices
• CPC Class Codes: G01N 2001/2276 Personal monitors
• CPC Class Codes: G01N 2001/4027 evaporation leaving a concentrated sample
• CPC Class Codes: Y10T 436/24 Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry

Abstract

The invention is directed to a system and method for detecting substances, such as high boiling and low vapor pressure materials, using high energy radiation imparted by a suitable radiation source, such as a strobe or laser over a short time period. The radiation source causes the materials to vaporize. A system handling system is used in conjunction with a detector to detect the presence of the materials including explosives, explosive-related compounds, chemical warfare agents, drugs, toxic industrial compounds, and derivatives thereof.

Claims

1. A method for detecting a high boiling point and/or a low vapor pressure material, comprising:

providing a housing comprising an inlet, a strobe, a gas source, and a detector, wherein the housing at least substantially surrounds the strobe and the inlet and wherein the inlet is positioned between the strobe and a surface potentially comprising a high boiling point and/or low vapor pressure material;

directing radiation from the strobe onto the surface to volatilize the high boiling point and/or low vapor pressure material, the directing radiation step is conducted over a time period of no more than about 1/100^th seconds;

transporting an airborne sample comprising at least a portion of any volatilized high boiling point and/or low vapor pressure materials on the surface through the inlet and through a heated conduit to the detector, wherein an internal surface of the heated conduit is maintained at a temperature sufficient to inhibit absorption and/or condensation of the high boiling point and/or low vapor pressure material on the internal surface, and wherein the heated conduit extends from the inlet to the detector; and

detecting whether or not the high boiling point and/or low vapor pressure material is present in the collected sample.

2. The method of claim 1, wherein said transporting further comprises directing a pressurized stream of gas from the gas source onto and/or around said surface at a flow rate sufficient to transport the gaseous stream and any high boiling point and/or low vapor pressure materials on the surface upward through the inlet of the housing and through the heated conduit after contact of the gaseous stream with the surface.

3. The method of claim 1, wherein said transporting step further comprises maintaining a negative pressure in the vicinity of the surface to draw said sample through the inlet of the housing and through the heated conduit.

4. The method of claim 1, wherein the temperature of the heated conduit ranges from about 100°

C. to about 250°

C., and wherein the temperature of the heated conduit is at least the condensation temperature of the material.

5. The method of claim 1, wherein the strobe comprises a xenon flash tube, and wherein said directing radiation step further comprises directing at least about 200 Joules of cumulative energy onto the surface.

6. The method of claim 1, wherein the high boiling point and/or low vapor pressure material is at least one of an explosive, an explosive related compound, a chemical warfare agent, a drug, a toxic industrial compound, and derivatives thereof, and wherein the radiation has one or more wavelengths in the range of from about 300 nm to about 700 nm in the visible region and/or from about 700 nm to about 2 microns in the infrared region of the electromagnetic spectrum.

7. The method of claim 1, wherein an offset distance between a surface of the strobe and the surface is no more than about 5 cm.

8. The method of claim 1, further comprising before the directing radiation step:

applying a volatilizing agent to the surface, wherein the volatilizing agent is at least one of water, a volatile organic solvent, and mixtures thereof;

wherein the strobe has an outputted energy profile, and wherein a peak of the profile is located in a radiation absorption band of the volatilizing agent.

9. The method of claim 1, wherein the strobe has an outputted energy profile, and wherein a peak of the profile is located in a radiation absorption band of the material.

10. A system for detecting a high boiling point and/or a low vapor pressure material, comprising:

a strobe operable to direct radiation onto a surface potentially comprising a high boiling point and/or low vapor pressure material over a time period of no more than about 1/100th seconds to volatilize the high boiling point and/or low vapor pressure material;

a housing at least substantially surrounding the strobe and an inlet to the housing, said housing comprising a sample handling system operable to collect an airborne sample comprising at least a portion of any volatilized high boiling point and/or low vapor pressure materials at and/or near the surface; and

a detector operable to detect whether or not the high boiling point and/or low vapor pressure material is present in the collected sample;

wherein said sample handling system comprises a heated conduit extending substantially from the inlet to the detector and a means for transporting said collected airborne sample through said heated conduit to said detector, wherein an internal surface of the heated conduit is maintained at a temperature sufficient to inhibit absorption and/or condensation of the high boiling point and/or low vapor pressure material on the internal surface.

11. The system of claim 10, further comprising a gas source for directing a stream of pressurized gas onto the surface at a flow rate sufficient to transport the gaseous stream and any high boiling point and/or low vapor pressure materials on said surface upward through the inlet of the housing and through the heated conduit after contact of the gaseous stream with the surface.

12. The system of claim 10, wherein the sample handling system further comprises a vacuum pump to maintain a negative pressure in the vicinity of the surface.

13. The system of claim 10, wherein the temperature of the heated conduit ranges from about 100°

C. to about 250°

C., and wherein the temperature of the heated conduit is at least the condensation temperature of the material.

14. The system of claim 10, wherein the strobe comprises a xenon flash tube wherein the high boiling point and/or low vapor pressure material is at least one of an explosive, an explosive related compound, a chemical warfare agent, a drug, a toxic industrial compound, and derivatives thereof, and wherein the radiation has one or more wavelengths in the range of from about 300 nm to about 700 nm in the visible region and/or from about 700 nm to about 2 microns in the infrared region of the electromagnetic spectrum.

15. The system of claim 10, further comprising an applicator operable to apply a volatilizing agent to the surface before radiation is contacted with the surface;

wherein the strobe has an outputted energy profile, and wherein a peak of the profile is located in a radiation absorption band of the volatilizing agent.

16. A system for detecting a high boiling point and/or a low vapor pressure material, comprising:

a strobe operable to direct radiation onto a surface potentially comprising a high boiling point and/or low vapor pressure material to volatilize the high boiling point and/or low vapor pressure material, wherein radiation emission cycles of the strobe are repeated at a frequency of at least about 0.2 Hz;

a housing at least substantially surrounding the strobe and an inlet to the housing, said housing comprising a sample handling system operable to collect an airborne sample comprising at least a portion of any volatilized high boiling point and/or low vapor pressure materials at and/or near the surface; and

a detector operable to detect whether or not the high boiling point and/or low vapor pressure material is present in the collected sample;

wherein said sample handling system comprises a heated conduit extending substantially from the inlet to the detector and a means for transporting said collected airborne sample through said heated conduit to said detector, wherein an internal surface of the heated conduit is maintained at a temperature sufficient to inhibit absorption and/or condensation of the high boiling point and/or low vapor pressure material on the internal surface.

17. The system of claim 16, further comprising a gas source for directing a stream of pressurized gas onto the surface at a flow rate sufficient to transport the gaseous stream and any high boiling point and/or low vapor pressure materials on said surface upward through the inlet of the housing and through the heated conduit after contact of the gaseous stream with the surface.

18. The system of claim 16, wherein the sample handling system further comprises a vacuum pump to maintain a negative pressure in the vicinity of the surface.

19. The system of claim 16, wherein the temperature of the heated conduit ranges from about 100°

C. to about 250°

C., and wherein the temperature of the heated conduit is at least the condensation temperature of the material.

20. The system of claim 16, wherein the heated conduit comprises a glass and/or ceramic surface adjacent the transported sample, and wherein the heated conduit comprises a silanizing agent.

21. The method system of claim 16, wherein the heated conduit comprises an at least substantially nonpolar surface adjacent the transported sample.

22. The system of claim 16, wherein the strobe comprises a xenon flash tube wherein the high boiling point and/or low vapor pressure material is at least one of an explosive, an explosive related compound, a chemical warfare agent, a drug, a toxic industrial compound, and derivatives thereof, and wherein the radiation has one or more wavelengths in the range of from about 300 nm to about 700 nm in the visible region and/or from about 700 nm to about 2 microns in the infrared region of the electromagnetic spectrum.