Abstract. Mid-infrared (MIR) laser spectroscopy measurements coupled with multivariate analysis (MVA) routines were applied to detection and classification of high explosives (HEs) deposited on aluminum and acrylonitrile butadiene styrene substrates. An MIR quantum cascade laser (QCL) was optically coupled to a grazing angle probe (QCL-GAP) mount to operate in diffuse reflectance mode at an incidence angle of 82 deg from the surface normal. The experimental conditions enabled reflection–absorption infrared reflectance spectroscopy of the laser light by the surface deposits of HEs and allowed obtaining spectra with high signal-to-noise ratios in a very short time. This optical arrangement permitted collecting data for identifying the vibrational signatures of the HEs to be detectable even at low surface concentrations. The HEs used included pentaerythritol tetranitrate, 1,3,5-trinitroperhydro-1,3,5-triazine, and 2,4,6-trinitrophenylmethylnitramine. Using principal components analysis, 100% of the HE samples deposited on the reflective and nonreflective substrate were correctly classified, avoiding false-positive responses in the analyses. The combination of QCL-GAP spectroscopy with MVA presented will also allow obtaining highly confident detections/identification of hazardous materials and other chemical/biological agents residing on both reflective and nonreflective surfaces. The methodology can easily be extended to other types of applications.

中文翻译：

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使用中红外激光光谱仪在多变量分析辅助的掠射入射角检测沉积在反射和无光泽基材上的高爆炸药样品

摘要。中红外 (MIR) 激光光谱测量与多变量分析 (MVA) 程序相结合，用于检测和分类沉积在铝和丙烯腈丁二烯苯乙烯基材上的高爆炸药 (HE)。中红外量子级联激光器 (QCL) 光学耦合到掠射角探头 (QCL-GAP) 安装座，以从表面法线 82 度的入射角以漫反射模式运行。实验条件允许通过 HE 表面沉积物对激光进行反射吸收红外反射光谱，并允许在很短的时间内获得具有高信噪比的光谱。这种光学布置允许收集用于识别 HEs 振动特征的数据，即使在低表面浓度下也能检测到。使用的 HE 包括季戊四醇四硝酸酯、1,3,5-trinitroperhydro-1,3,5-triazine 和 2,4,6-trinitrophenylmethylnitramine。使用主成分分析，100% 沉积在反射和非反射基板上的 HE 样品被正确分类，避免了分析中的假阳性响应。QCL-GAP 光谱与 MVA 相结合，还可以对存在于反射和非反射表面上的有害物质和其他化学/生物制剂进行高度可靠的检测/识别。该方法可以很容易地扩展到其他类型的应用程序。沉积在反射和非反射基板上的 HE 样品 100% 被正确分类，避免了分析中的假阳性响应。QCL-GAP 光谱与 MVA 相结合，还可以对存在于反射和非反射表面上的有害物质和其他化学/生物制剂进行高度可靠的检测/识别。该方法可以很容易地扩展到其他类型的应用程序。沉积在反射和非反射基板上的 HE 样品 100% 被正确分类，避免了分析中的假阳性响应。QCL-GAP 光谱与 MVA 相结合，还可以对存在于反射和非反射表面上的有害物质和其他化学/生物制剂进行高度可靠的检测/识别。该方法可以很容易地扩展到其他类型的应用程序。