Apparatus for detection of certain nitrogen-containing gases using chemiluminescence

• US 4,765,961 A
• Filed: 04/30/1984
• Issued: 08/23/1988
• Est. Priority Date: 04/30/1984
• Status: Expired due to Term

• Current Assignee: Scintrex Ltd. (LaCoste & Romberg Scintrex, Inc.), University of Michigan
• Original Assignee: Scintrex Ltd. (LaCoste & Romberg Scintrex, Inc.), University of Michigan
• Inventors: Schiff, Harold I., Stedman, Donald H.
• Primary Examiner(s): Richman, Barry S.
• Assistant Examiner(s): KRYZA, LYNN M
• Application Number:
  US06/605,599
• Time in Patent Office: 1,576 Days
• Field of Search: 422/52, 422/86, 422/87, 422/91, 436/56, 436/110, 436/116-118, 436/52, 436/135, 436/172, 436/169, 435/8
• US Class Current: 422/52
• CPC Class Codes: G01N 21/766 of gases
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/179228 Both nitrogen oxide and dioxide

Abstract

Chemiluminescence is detected in a luminol solution free of metal ions flowing through a porous material to indicate the presence of certain nitrogen-containing gases. Continuous monitoring of atmosphoric gases is possible through use of the described methods and related apparatus.

Claims

1. Apparatus for detecting the presence of, and measuring, nitrogen gases in a gas sample, the apparatus comprising:

means defining a reaction region for receiving a gas sample;

a gas inlet positioned and arranged for supplying a gas sample to said means defining a reaction region;

a gas outlet positioned and arranged for removing a gas sample from said means defining a reaction region;

a luminol inlet positioned and arranged for transferring to said means defining a reaction region a luminol solution free from metal ions;

a porous material positioned and arranged to be substantially stationary by stationary support means in said means defining a reaction region, said porous material having a receiving portion thereof positioned in the vicinity of said luminol inlet and arranged to communicate and receive luminol solution from said luminol inlet, said porous material providing a path for the luminol solution to flow therethrough by wicking, in the presence of a gas sample, and providing a surface on which the gas sample reacts with the luminol solution while the luminol solution flows through said path;

a receiving reservoir positioned and arranged for receiving the luminol solution after flowing through said path of said porous material and reacting with the gas sample; and

photomultiplier means arranged in the vicinity of said means defining a reaction region, positioned and arranged for detecting and measuring chemiluminescence the luminol solution.

2. Apparatus according to claim 1 wherein said porous material is a filter paper.

3. Apparatus according to claim 1 wherein said porous material is selected from at least one of the group consisting of glass fibres, cellulose fibres, and glass frit.

4. Apparatus according to claim 1 including a trap containing a selectable one of FeSO₄ and FeSO₄ suspended on silica gel through which said gas sample is passed before contacting the luminol solution, thereby scrubbing NO₂ from the gas sample.

5. Apparatus according to claim 1 including a trap containing CrO₃ through which the gas sample is passed before contacting the luminol solution, thereby oxidizing NO in the gas sample to NO₂.

6. Apparatus according to claim 1 including means for selectably adding nitric oxide at said gas inlet, thereby enabling ozone to be measured.

7. The apparatus of claim 1 wherein there is further provided a supply reservoir coupled to said luminol inlet for receiving and containing a supply of luminol solution, said porous material extending into said supply reservoir for communicating with the supply of luminol solution contained therein.

8. Apparatus according to claim 1 including a trap containing at least one of cotton wool and animal hair through which the gas sample is passed before contacting the luminol solution, thereby scrubbing O₃ from the gas sample.

9. Apparatus according to claim 8 including a second trap containing FeSO₄ through which the gas sample is passed before contacting the luminol solution, thereby scrubbing NO₂ from the gas sample, a third trap containing CrO₃ through which the gas sample is passed before contacting the luminol solution, thereby oxidizing NO in the gas sample to NO₂, and means for selectively passing and bypassing said traps with the gas sample.