Granted Patent B2

US 12,411,122 · App. 17/318,917 · Granted Sep 9, 2025

Inventors: Udo H. Verkerk (Toronto, CA); Vladimir Romanov (Pelham, NH); Hartwig Schmidt (Tewksbury, MA); Stefan Lukow (Windham, NH); Robert MacRae (Ayer, MA); Zachary Andersen (Andover, MA)

Assignee: Rapiscan Systems, Inc.

G01N33/227G01N33/15

Abstract

Claims (36)

1. A method of manufacturing a sensitivity trap, wherein the sensitivity trap comprises a polymer matrix made of a polymer material, and at least one analyte embedded within the polymer matrix, and wherein the sensitivity trap is defined by a target glass transition temperature, the method comprising:

selecting an amount and a type of plasticizer, wherein the amount and the type of the plasticizer is based upon a type of the at least one analyte and at least one of the target glass transition temperature or a diffusion coefficient of the at least one analyte and wherein said amount of plasticizer is sufficient to increase a diffusion coefficient of the at least one analyte such that, when the sensitivity trap is inserted into an ion mobility spectrometer (IMS) and exposed to a heating rate of approximately 33° C. per second, the at least one analyte is released from the mixture with sufficient desorption intensity to reach at least 2000 a.u. as measured by the IMS within 4 seconds of initiating heating;

dissolving a polymer and the selected amount and type of plasticizer in a solvent to form a mixture;

adding the at least one analyte to the mixture;

removing the solvent from the mixture; and

depositing the mixture onto a carrier to form the sensitivity trap.

2. The method of claim 1 , further comprising depositing a predefined amount of the mixture on a surface.

3. The method of claim 1 , wherein the at least one analyte comprises at least one of an explosive material, a narcotic material, or a combination of an explosive and a narcotic material.

4. The method of claim 1 , wherein an amount of the at least one analyte in the polymer matrix is less than 100 nanograms.

5. The method of claim 1 , wherein the at least one analyte comprises at least one of a nitroaromatic composition, a nitramine composition, a nitro-ester composition, a nitrate composition, or a peroxide composition.

6. The method of claim 1 , wherein the polymer is a polycarbonate composition.

7. The method of claim 6 , further comprising adjusting the target glass transition temperature.

8. The method of claim 7 , wherein the plasticizer is diisooctyl phthalate.

9. The method of claim 8 , wherein the target glass transition temperature is in a range of −30 to 140 degrees Celsius.

10. The method of claim 1 , further comprising determining a rate of release of the analyte from the sensitivity trap by adjusting the amount and type of the plasticizer.

11. The method of claim 1 , wherein the polymer material is a polycarbonate composition and wherein the plasticizer is diisooctyl phthalate.

12. The method of claim 11 , wherein the amount of the plasticizer is between 4 and 24 W t percent.

13. The method of claim 11 , wherein the amount of the plasticizer is approximately 14 W t percent.

14. The method of claim 1 , wherein the plasticizer is at least one of tributyl citrate, acetyl triethyl citrate, diisooctyl phthalate, or triisononyl trimellitate.

15. The method of claim 1 , wherein the polymer material is at least one of an inert organic polymer material, polystyrene, polycarbonate, or polylactic-co-glycolic acid.

16. The method of claim 1 , wherein the carrier comprises at least one of metal, glass and ceramic material.

17. A sensitivity trap defined by a target glass transition temperature, comprising:

a polymer matrix made of a polymer material;

at least one analyte embedded within the polymer matrix;

a plasticizer, wherein an amount and a type of the plasticizer is based upon the target glass transition temperature and a type of the at least one analyte and wherein said amount of plasticizer is sufficient to increase a diffusion coefficient of the at least one analyte such that, when the sensitivity trap is inserted into an ion mobility spectrometer (IMS) and exposed to a heating rate of approximately 33° C. per second, the at least one analyte is released from the mixture with sufficient desorption intensity to reach at least 2000 a.u. as measured by the IMS within 4 seconds of the onset of heating; and

a carrier material upon which the polymer matrix, at least one analyte, and plasticizer are deposited.

18. The sensitivity trap of claim 17 , wherein the at least one analyte comprises at least one of an explosive material, a narcotic material, or a combination of an explosive and a narcotic material.

19. The sensitivity trap of claim 18 , wherein the explosive material comprises at least one of a nitroaromatic composition, a nitramine composition, a nitro-ester composition, a nitrate composition, or a peroxide composition.

20. The sensitivity trap of claim 17 , wherein an amount of the at least one analyte in the polymer matrix is less than 100 nanogram in a solvent-cast membrane.

21. The sensitivity trap of claim 17 , wherein the polymer material is a polycarbonate composition and wherein the plasticizer is diisooctyl phthalate.

22. The sensitivity trap of claim 21 , wherein the amount of the plasticizer is between 4 and 24 W t percent.

23. The sensitivity trap of claim 21 , wherein the amount of the plasticizer is approximately 14 W t percent.

24. The sensitivity trap of claim 21 , wherein the glass transition temperature is in a range of −30 to 140 degrees Celsius.

25. The sensitivity trap of claim 17 , wherein the plasticizer is at least one of tributyl citrate, acetyl triethyl citrate, diisooctyl phthalate, or triisononyl trimellitate.

26. The sensitivity trap of claim 17 , wherein the polymer material is at least one of an inert organic polymer material, polystyrene, polycarbonate, or polylactic-co-glycolic acid.

27. The sensitivity trap of claim 17 , wherein the carrier material is at least one of metal, glass and ceramic.

Assignments (2)

Continuity (2)

References Cited (217)