Method and apparatus for detecting chemical contamination

• US 20040011965A1
• Filed: 07/01/2003
• Published: 01/22/2004
• Est. Priority Date: 08/18/2000
• Status: Abandoned Application

• Current Assignee: Lattice Intellectual Property Limited
• Original Assignee: Lattice Intellectual Property Limited
• Inventors: Hodgkinson, Elizabeth Jane
• Application Number:
  US10/344,417
• Publication Number:
  US 20040011965A1
• Time in Patent Office: Days
• US Class Current: 250/461.1
• CPC Class Codes: G01N 2021/6423 Spectral mapping, video display
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence

Abstract

The method detects the presence of poly-chlorinated biphenyls on a surface, by the use of UV fluorescence spectroscopy in the back-emitting mode. The apparatus comprises a source of UV radiation. Exposure means are provided for conveying UV radiation from the source to the surface. Collecting means collect radiation back-emitted from the surface. A filter filters the collected radiation, and a spectrometer analyses the filtered collected radiation. The filter allows radiation having a wavelength within the range of from 320 nm to 360 nm to pass to the spectrometer.

Claims

1. A method of detecting the presence of poly-chlorinated biphenyls on or in a sample, comprising the use of UV fluorescence spectroscopy.

2. A method according to claim 1, comprising exposing said sample to radiation from a UV light source, filtering the radiation emitted from said sample and subjecting said filtered emitted radiation to spectral analysis.

3. A method according to claim 2, wherein said sample is exposed to radiation having a band width of less than 10 nm.

4. A method according to claim 2 or 3, wherein said sample is exposed to radiation having a peak emission within the range 215 to 270 nm.

5. A method according to any one of claims 2, 3 or 4, wherein said spectral analysis is carried out at a resolution of less than 10 nm.

6. A method according to any one of claims 2 to 5, wherein said spectral analysis is carried out over at least one wavelength band within the range from the peak emission wavelength of the exposing radiation to 450 nm.

7. A method according to claim 6, wherein said sample is suspected of contamination with another contaminant, and wherein spectral analysis is carried out over at least two wavelength bands, being (i) a first band within the range of 320 to 360 nm;

and (ii) a second band within which fluorescence from said PCB contaminant is not expected.

8. A method according to claim 7, wherein said second band lies within the range of 300 to 320 nm or 360 to 430 nm.

9. A method according to any of claims 1 to 8, wherein said sample is a liquid.

10. A method according to any of claims 1 to 8, wherein said sample is the surface of a solid.

11. An apparatus for detecting the presence of poly-chlorinated biphenyls on or in a sample, comprising a source of UV radiation, exposure means for conveying UV radiation from said source to said sample, collecting means for collecting radiation emitted from said sample, a filter for filtering said collected radiation, and a spectrometer for analysing the filtered collected radiation, characterised in that said filter allows radiation having a wavelength within the range of from 320 nm to 360 nm to pass to said spectrometer.

12. An apparatus according to claim 11, wherein said collecting means includes optical fibres extending from a vicinity of said sample to said spectrometer.

13. An apparatus according to claim 11 and 12, wherein said exposure means includes optical fibres extending from said source to the vicinity of said sample.

14. An apparatus according to claims 12 and 13, adapted for detecting the presence of poly-chlorinated biphenyls on the inside surface of a pipe, wherein said exposure means and said filter are housed in a common probe positioned in said pipe, said spectrometer is located outside said pipe, and an optical fitting is positioned in a wall of the pipe and is optically coupled to said probe and to said spectrometer by said optical fibres.

15. An apparatus according to claim 14, wherein said probe is adapted for insertion into a gas main under live conditions.

16. An apparatus according to any of claims 11 to 15, wherein the spectrometer is configured for detection of back-emitted radiation from the sample.

17. A method of detecting the presence of poly-chlorinated biphenyls on a surface, substantially as hereinbefore described, with reference to the accompanying examples.

18. An apparatus for detecting the presence of poly-chlorinated biphenyls on a surface, substantially as hereinbefore described, with reference to the accompanying drawings.