Method and composition for detecting oxidizing salts

Patent metadata

Field	Value
Publication number	US-9068960-B2
Application number	US-201213650820-A
Country	US
Kind code	B2
Filing date	Oct 12, 2012
Priority date	Oct 12, 2012
Publication date	Jun 30, 2015
Grant date	Jun 30, 2015

Abstract

The present invention provides methods for determining the presence of oxidizing salts. According to the current invention, analyte is collected on a swipe and subsequently heated to a temperature sufficient to release a detectable vapor phase component of the oxidizing salt. The vapor phase component passes reacts with a pH sensitive molecule. Reaction of the vapor phase product with the pH sensitive molecule produces a detectable change in response intensity.

First claim

We claim:

1. A method for determining the presence of an oxidizing salt comprising:
collecting the oxidizing salt with a sampling material;
presenting the sampling material to a sensor assembly, said sensor assembly including a solid substrate carrying a pH sensitive molecule, the pH sensitive molecule undergoing stimulation by an excitation source, said excitation source emitting light radiation at wavelengths between about 325 nm and about 700 nm, while monitoring the response of the pH sensitive molecule to the stimulation with a light sensor suitable for detecting changes in response intensity;
heating the sampling material to a temperature sufficient to induce evaporative dissociation of the oxidizing salt thereby yielding evaporative dissociation compounds of the oxidizing salt;
passing the evaporative dissociation compounds of the oxidizing salt into said sensor assembly and reacting said pH sensitive molecule with at least one dissociation compound;
monitoring said pH sensitive molecule with said light sensor to determine any change in response intensity wherein a change in response intensity indicates the presence of oxidizing salt.

2. The method of claim 1 , wherein said pH sensitive molecule is selected from the group consisting of:
SNARF®-5F, 5-(and-6)-carboxylic acid as represented by the following structure where the carboxylic acid group may be positioned at either the indicated 5 or 6 position,

SNARF®-4F, 5-(and-6)-carboxylic acid as represented by the following structure where the carboxylic acid group may be positioned at either the indicated 5 or 6 position,

5-(and-6)-carboxy SNARF®-1, as represented by the following structure where the carboxylic acid group may be positioned at either the indicated 5 or 6 position,

LysoSensor™ Green DND-153 as represented by the following structure,

2′,7′-difluorofluorescein as represented by the following structure,

2-[5-methoxy-2-(4-phenyl-quinoline-2yl)-phenyl]-ethanol as represented by the following structure

and,
2-{2-[-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-methoxy-phenyl}-4-phenyl-quinoline as represented by the following structure

3. The method of claim 1 , wherein the sensor assembly operates at a temperature lower than the temperature required to induce evaporative dissociation of the oxidizing salt.

4. The method of claim 3 , wherein the sensor assembly operates at a temperature between about 25° C. and about 100° C.

5. The method of claim 3 , wherein the sensor assembly operates at a temperature between about 35° C. and about 85° C.

6. The method of claim 3 , wherein the sensor assembly operates at a temperature between about 45° C. and about 70° C.

7. The method of claim 3 , wherein the flow rate of vapors through the sensor assembly is sufficient to substantially prelude condensation of vapors on the interior of the sensor assembly.

8. The method of claim 3 , wherein the flow rate of vapors through the sensor assembly is between about 10 cm 3 /minute and about 200 cm 3 /minute.

9. The method of claim 3 , wherein the flow rate of vapors through the sensor assembly is between about 20 cm 3 /minute and about 60 cm 3 /minute.

10. The method of claim 1 , wherein said sensor assembly includes a sample tip providing fluid communication between the interior and exterior of said sensor assembly and wherein said sample tip assembly is heated to the temperature sufficient to induce evaporative dissociation and further comprising the step of contacting said sample tip assembly with said sampling material thereby inducing evaporative dissociation of any oxidizing salt collected on said sampling material.

11. The method of claim 1 , wherein the acid component of the evaporative dissociation compounds of the oxidizing salt released from the sampling material pass along said solid substrate, reacting with said pH sensitive molecule producing a change in response intensity detectable by the light sensor.

12. A method for determining the presence of oxidizing salt on a surface comprising:
contacting a surface suspected of carrying an oxidizing salt selected from the group consisting of ammonium nitrate, urea nitrate, guanidine nitrate and ammonium perchlorate with a sampling material thereby collecting a sample from said surface;
presenting the sampling material to a sensor assembly, said sensor assembly including a solid substrate carrying a pH sensitive molecule, the pH sensitive molecule undergoing stimulation by an excitation source, said excitation source emitting light radiation at wavelengths between about 325 nm and about 700 nm, while monitoring the response of the pH sensitive molecule to the stimulation with a light sensor suitable for detecting changes in response intensity;
heating the sampling material to a temperature sufficient to induce evaporative dissociation of the oxidizing salt thereby yielding evaporative dissociation compounds of ammonium nitrate;
passing the evaporative dissociation compounds into said sensor assembly and reacting said pH sensitive molecule with said dissociation compounds;
monitoring said pH sensitive molecule with said light sensor for a change in response intensity thereby indicating the presence of an oxidizing salt on the sampled surface.

13. The method of claim 12 , wherein the step of heating the sampling material takes place at a temperature of about 100° C. to about 160° C. when the oxidizing salt is believed to be ammonium nitrate.

14. The method of claim 12 , wherein the step of heating the sampling material takes place at a temperature of about 90° C. to about 120° C. when the oxidizing salt is believed to be urea nitrate.

15. The method of claim 12 , wherein the step of heating the sampling material takes place at a temperature of about 210° C. to about 225° C. when the oxidizing salt is believed to be guanidine nitrate.

16. The method of claim 12 , wherein the step of heating the sampling material takes place at a temperature of about 250° C. to about 350° C. when the oxidizing salt is believed to be ammonium perchlorate.

17. The method of claim 12 , wherein said pH sensitive molecule is selected from the group consisting of:
SNARF®-5F, 5-(and-6)-carboxylic acid as represented by the following structure where the carboxylic acid group may be positioned at either the indicated 5 or 6 position,

SNARF®-4F, 5-(and-6)-carboxylic acid as represented by the following structure where the carboxylic acid group may be positioned at either the indicated 5 or 6 position,

5-(and-6)-carboxy SNARF®-1, as represented by the following structure where the carboxylic acid group may be positioned at ei

Assignees

• Wald Lara Beth
• Frye-Mason Gregory Charles
• Flir Systems

Inventors

• Wald Lara Beth
• Frye-Mason Gregory Charles

Classifications

• Y10T436/173845

  Amine and quaternary ammonium · CPC title

• G01N21/643

  non-biological material · CPC title

• Y10T436/173076

  Nitrite or nitrate · CPC title

• G01N31/227 Primary

  for nitrates or nitrites · CPC title

• G01N2201/062

  LED's · CPC title