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Proceedings Paper

Detection of 2,4,6-trinitrotoluene on non-traditional surfaces using fiber optic coupled grazing angle probe: FTIR
Author(s): Oliva M. Primera-Pedrozo; Nelmarie Rodríguez; Leonardo Pacheco-Londoño; Samuel P. Hernández-Rivera
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Paper Abstract

With heightened awareness of Homeland Security issues, the detection of explosive has become a pressing priority. Explosives detection is a very important task for National Security: threat compounds need to be detected on a variety of surfaces. Every surface will interact with the target compounds in a very unique manner and the degree of adhesion will vary from surface to surface. The formidable task includes development of new probes and methods for detection of concealed explosives. Fiber Optic Coupled Infrared Spectroscopy has been used as a potential technique to develop new methodologies for detection of explosives on surfaces. On one of such proposed methodologies involves a Grazing Angle Probe rendering the latter as a remote sensed, in situ and capability of detecting nanograms/cm2 of the compounds. In this research a smearing technique was used for transferring the target analytes onto the substrates to be used as standards. Smearing was also used as a sample transfer method of the threat agents to target surfaces. One of the most relevant areas of investigation is to analyze 2,4,6-trinitrotoluene (TNT) on various non traditional surfaces such as plastics. The work also centered in to obtaining an optimization method where a more accurate spectrum could be obtained and a better spectroscopic preprocessing routine could be applied. A series of statistical methods can be used for quantification of TNT on plastic surfaces, among these are: peak height analysis and peak areas integration. Both of these can be coupled to Partial least squares regression, which is an extension of multiple linear regression models. Using peak areas in the range from 1380 to 1273 cm-1, the method was found to be linear for loading concentration lower than 5.0 μg/cm2. A loading concentration of 0.62 μg/cm2 (620 ng/cm2) was considered as limit of quantification and 0.16 μg/cm2 (160 ng/cm2) as limit of detection.

Paper Details

Date Published: 14 May 2007
PDF: 10 pages
Proc. SPIE 6542, Infrared Technology and Applications XXXIII, 65423J (14 May 2007); doi: 10.1117/12.720405
Show Author Affiliations
Oliva M. Primera-Pedrozo, Univ. of Puerto Rico Mayagüez (United States)
Nelmarie Rodríguez, Univ. of Puerto Rico Mayagüez (United States)
Leonardo Pacheco-Londoño, Univ. of Puerto Rico Mayagüez (United States)
Samuel P. Hernández-Rivera, Univ. of Puerto Rico Mayagüez (United States)

Published in SPIE Proceedings Vol. 6542:
Infrared Technology and Applications XXXIII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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