Method for the detection of nitro-containing compositions using ultraviolet photolysis

• US 6,051,436 A
• Filed: 08/03/1994
• Issued: 04/18/2000
• Est. Priority Date: 08/03/1994
• Status: Expired due to Fees

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Original Assignee: Lockheed Idaho Technologies Company
• Inventors: Moore, Glenn A., Reagen, William K., Lancaster, Gregory D., Partin, Judy K.
• Primary Examiner(s): Soderquist, Arlen
• Application Number:
  US08/285,584
• Time in Patent Office: 2,085 Days
• Field of Search: 422/52, 436/106, 436/107, 436/110, 436/153, 436/172, 436/181, 436/116-118
• US Class Current: 436/106
• CPC Class Codes: G01N 21/631 using photolysis and investigating photolysed fragments
• CPC Class Codes: G01N 31/005 investigating the presence of an element by oxidation G01N31/12 takes precedence
• CPC Class Codes: G01N 33/0037 for NOx
• CPC Class Codes: G01N 33/188 Determining the state of nitrification biological treatment of water by aerobic or anaerobic processes for denitrification of water C02F3/305
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y10T 436/17 Nitrogen containing
• CPC Class Codes: Y10T 436/170769 N-Nitroso containing [e.g., nitrosamine, etc.]
• CPC Class Codes: Y10T 436/173076 Nitrite or nitrate
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/25875 Gaseous sample or with change of physical state

Abstract

A method for detecting nitro-containing compositions (e.g. nitrate/nitrite materials) in water samples and on solid substrates. In a water sample, ultraviolet light is applied to the sample so that dissolved nitro compositions therein will photolytically dissociate into gaseous nitrogen oxides (NO₂(g) and/or NO.sub.(g)). A carrier gas is then introduced into the sample to generate a gaseous stream which includes the carrier gas combined with any gaseous nitrogen oxides. The carrier gas is thereafter directed into a detector. To detect nitro-compositions on solid substrates, ultraviolet light is applied thereto. A detector is then used to detect any gaseous nitrogen oxides which are photolytically generated during ultraviolet illumination. An optional carrier gas may be applied to the substrate during illumination to produce a gaseous stream which includes the carrier gas and any gaseous nitrogen oxides. The gaseous stream is then supplied to the detector.

Claims

1. A method for analyzing a sample of solid material for the presence of nitro-containing compositions thereon, said method comprising the steps of:

providing an ultraviolet light source for generating ultraviolet light;

providing a sample of solid material comprising an uncovered and exposed surface, said uncovered and exposed surface allowing said ultraviolet light from said ultraviolet light source to be applied to said solid material without passing through any intervening structures;

positioning said ultraviolet light source directly above said uncovered and exposed surface of said solid material in order to create an uninterrupted gap between said solid material and said light source;

activating said ultraviolet light source so that said light source delivers said ultraviolet light into said gap and onto said uncovered and exposed surface of said solid material without interruption by any intervening structures, said ultraviolet light photolytically dissociating any of said nitro-containing compositions on said solid material into gaseous nitrogen oxides, said gaseous nitrogen oxides rising upwardly from said surface of said solid material;

providing gas detector means for detecting gaseous nitrogen oxides;

positioning at least a portion of said gas detector means above said uncovered and exposed surface of said solid material in order to create an uninterrupted gap between said solid material and said gas detector means so that any of said gaseous nitrogen oxides generated during delivery of said ultraviolet light onto said solid material will enter into said portion of said gas detector means without interruption by any intervening structures; and

activating said gas detector means in order to determine if any of said gaseous nitrogen oxides were generated during delivery of said ultraviolet light onto said solid material.

2. A method for analyzing a sample of solid material for the presence of nitro-containing compositions thereon, said method comprising the steps of:

providing an ultraviolet light source for generating ultraviolet light;

providing a sample of solid material comprising an uncovered and exposed surface, said uncovered and exposed surface allowing said ultraviolet light from said ultraviolet light source to be applied to said solid material without passing through any intervening structures;

positioning said ultraviolet light source directly above said uncovered and exposed surface of said solid material in order to create an uninterrupted gap between said solid material and said light source;

activating said ultraviolet light source so that said light source delivers said ultraviolet light into said gap and onto said uncovered and exposed surface of said solid material without interruption by any intervening structures, said ultraviolet light photolytically dissociating any of said nitro-containing compositions on said solid material into gaseous nitrogen oxides, said gaseous nitrogen oxides rising upwardly from said surface of said solid material;

providing gas detector means for detecting gaseous nitrogen oxides;

passing a stream of at least one carrier gas over said surface of said solid material during delivery of said ultraviolet light onto said solid material, said carrier gas combining with any of said gaseous nitrogen oxides produced during delivery of said ultraviolet light in order to generate a gaseous stream which comprises said carrier gas in combination with said gaseous nitrogen oxides;

positioning at least a portion of said gas detector means above said uncovered and exposed surface of said solid material in order to create an uninterrupted gap between said solid material and said gas detector means so that said gaseous stream will enter into said portion of said gas detector means without interruption by any intervening structures; and

activating said gas detector means in order to determine if any of said gaseous nitrogen oxides are present in said gaseous stream.