A standoff multivariate calibration for detection of highly energetic materials (HEM) using Fourier transform infrared
spectroscopy is presented in this report. The procedure consists in standoff sensing at 1 m distance and the variation of
three parameters of detection. The first variable considered was the angular dependence: 0° to 45‡ from source-target with respect to alignment of target-detector. The second variable consisted on the use of several surfaces on which the material was deposited. The substrates used were polished aluminum and anodized aluminum. The third variable studied was the dependence on some specific analyte loading surface concentration: from 10 μg/cm<sup>2</sup> to200 μg/cm<sup>2</sup>. The HEM
used in this work was PETN, synthesized in our lab. Calibration curves were based on the use of chemometrics routines
such as partial least squares (PLS) regression analysis. This algorithm was used to evaluate the impact of the angular
dependence about the limits of detection of different HME loadings on aluminum substrates.