Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

• US 5,525,520 A
• Filed: 05/09/1994
• Issued: 06/11/1996
• Est. Priority Date: 09/01/1992
• Status: Expired due to Fees

• Current Assignee: Martin Marietta Energy Systems, Inc.
• Original Assignee: Martin Marietta Energy Systems, Inc.
• Inventors: Dinh, Tuan V.
• Primary Examiner(s): Bhat, N.
• Application Number:
  US08/239,821
• Time in Patent Office: 764 Days
• Field of Search: 422/82.08, 422/82.06, 422/82.07, 436/126, 436/165, 436/172, 356/317, 356/318, 356/417
• US Class Current: 436/126
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/75 Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated systems in which material is burnt in a flame or plasma G01N21/72, G01N21/73
• CPC Class Codes: G01N 33/0049 for halogenated organic compounds
• CPC Class Codes: G01N 33/1826 organic contamination in water
• CPC Class Codes: G01N 33/24 Earth materials G01N33/42 takes precedence
• CPC Class Codes: Y10T 436/196666 Carbon containing compound [e.g., vinylchloride, etc.]

Abstract

A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate therethrough to the photo-activator and thereby form the complex.

Claims

1. A method of testing for the presence of an organochloride contaminant, comprising the steps of:

exposing a probe containing a photo-activator to a sample suspected of containing the organochloride contaminant so that the organochloride, if present, and the photo-activator form a complex;

irradiating the photo-activator/contaminant complex with UV light at a first wavelength for a time sufficient to form a photo-product; and

detecting the photo-product, the presence of the photo-product being indicative of the presence of the organochloride contaminant.

2. The method of claim 1, wherein the detecting step comprises irradiating the photo-product with a light of a second wavelength to cause the photo-product to luminesce, the luminescence of the photo-product complex being indicative of the presence of organochloride contaminant.

3. The method of claim 1, wherein the detecting step comprises exposing the photo-product to a scanning light having a range of wavelength and measuring absorption of the scanning light by the photo-product.

4. The method of claim 1, wherein the detecting step comprises exposing the photo-product to a scanning light having a range of wavelength and measuring reflection of the scanning light from the photo-product.

5. The method of claim 1, wherein the detecting step comprises exposing the photo-product to a scanning light having a range of wavelengths and measuring scattering of the scanning light from the photo-product.

6. The method of claim 1, wherein the detecting step comprises observing color change of the photo-product.

7. A probe for use in detecting an organochloride contaminant, comprising:

a body adapted to contain a quantity of photo-activator;

a light interface for introducing light from a source into the body; and

a contaminant interface through which the organochloride contaminant, if present, passes to react with the photo-activator and thereby form a photo-product when exposed to light through the light interface.

8. A probe according to claim 7, wherein the body comprises a cylindrical member having open opposite axial ends.

9. A probe according to claim 8, wherein the light interface is at least one fiber optic fitted into one end of the cylindrical member.

10. A probe according to claim 9, wherein the contaminant interface comprises a porous membrane fitted over the other end of the cylindrical member, and being transmissive of the organochloride contaminant.

11. A probe according to claim 7, wherein the contaminant interface comprises a porous membrane fitted over the other end of the cylindrical member, and being transmissive of the organochloride contaminant.

12. A probe according to claim 7, further comprising a chamber disposed within the cylindrical member for containing the photo-activator.

13. A probe according to claim 7, further comprising means for communicating photo-activator to and from the body.

14. A probe according to claim 13, wherein the communicating means comprises at least one conduit extending into the body.

15. A probe according to claim 7, wherein the contaminant interface comprises a gas inlet and a gas outlet formed in the body.

16. A probe according to claim 15, further comprising a pump connected to one of the gas inlet and gas outlet for circulating gas through the body.

17. An apparatus for determining the presence of an organochloride contaminant, comprising:

a probe having means for containing a photo-activator and an interface through which a sample suspected of containing the organochloride contaminant is contacted so that the organochloride, if present, and the photoactivator from a complex;

means, optically coupled to the probe, for irradiating the photo-activator/contaminant complex with light at a first wavelength for a time sufficient to form a photo-product; and

means, optically coupled to the probe, for detecting the photo-product, the presence of the photo-product being indicative of the presence of the organochloride contaminant.

18. An apparatus according to claim 17, wherein the irradiating means comprises a light source and a bifurcated optical fiber having a first portion communicating excitation light to the probe and a second portion communicating emission light to the detecting means.

19. An apparatus according to claim 17, wherein the irradiating means comprises a light source, a mirror disposed between the light source and the probe and having a pinhole for through which excitation light passes through to the probe, and a single optical fiber disposed between the mirror and the probe, emission light being reflected from the mirror to the detecting means.