National Electronics and Computer Technology Center, 112 Thailand Science Park, Pathumthani, Thailand.
Forensic Sci Int. 2013 Dec 10;233(1-3):174-8. doi: 10.1016/j.forsciint.2013.09.012. Epub 2013 Sep 17.
Recent analyses by ion-exchange chromatography (IC) showed that, beside nitrate, the majority of the industrial-grade emulsion explosives, extensively used by most separatists in the southern Thailand insurgency, contained small traces of perchlorate anions. In demand for the faster, reliable, and simple detection methods, the portable detection of nitrate and perchlorate became the great interest for the forensic and field-investigators. This work proposed a unique method to detect the trace amount of perchlorate in seven industrial-grade emulsion explosives under the field tests. We utilized the combination of the portable Raman spectroscope, the developed surfaced-enhanced Raman substrates, and the sample preparation procedures. The portable Raman spectroscope with a laser diode of 785 nm for excitation and a thermoelectric-cooled CCD spectrometer for detection was commercially available. The SERS substrates, with uniformly distributed nanostructured silver nanorods, were fabricated by the DC magnetron sputtering system, based on the oblique-angle deposition technique. The sample preparation procedures were proposed based on (1) pentane extraction technique and (2) combustion technique, prior to being dissolved in the purified water. In comparison to the ion chromatography and the conventional Raman measurements, our proposed methods successfully demonstrated the highly sensitive detectability of the minimal trace amount of perchlorate from five of the explosives with minimal operating time. This work was therefore highly practical to the development for the forensic analyses of the post-blast explosive residues under the field-investigations.
最近的离子交换色谱（IC）分析表明，除硝酸盐外，在泰国南部叛乱中大多数分离分子广泛使用的工业级乳化炸药还含有少量的过氯酸盐阴离子。为了满足对更快、更可靠和更简单的检测方法的需求，便携式硝酸盐和过氯酸盐检测成为法医和现场调查人员的极大兴趣。本工作提出了一种独特的方法，用于在现场测试下检测七种工业级乳化炸药中痕量的过氯酸盐。我们利用便携式拉曼光谱仪、开发的表面增强拉曼基底和样品制备程序的组合。用于激发的 785nm 激光二极管和用于检测的热电冷却 CCD 光谱仪的便携式拉曼光谱仪可从商业途径获得。基于斜角沉积技术的直流磁控溅射系统制造了具有均匀分布纳米结构银纳米棒的 SERS 基底。根据（1）戊烷萃取技术和（2）燃烧技术，提出了样品制备程序，然后将其溶解在纯净水中。与离子色谱和常规拉曼测量相比，我们提出的方法成功地展示了从五种炸药中检测痕量过氯酸盐的高灵敏度，操作时间最短。因此，这项工作非常适合在现场调查中对爆炸残留物进行法医分析的发展。
