Infrared and Raman spectroscopy techniques applied to identification of explosives

Recent advances in capillary electrophoresis instrumentation for the analysis of explosives

“…[2] This technique possesses some advantages which make it ideal for explosive analysis. On the one hand, samples can be analysed directly in the equipment, thus making sample preparation easier compared to other separation techniques.…”

“…Depending on their chemical structure, use or nature, explosives have been classified at different levels. [1,2] For example, they can be divided into high-order explosives (expansion speed range: between 50,000 and 10,000 m/s) or low-order explosives (expansion speed range: between 300 and 3000 m/s). High-order explosives can be subcategorized into primary explosives, such as nitroglycerin (NG), hexamethylenetriperoxide diamine (HMTD) or triacetonetriperoxide (TATP), which are less stable, and thus used in small quantities in primers or detonators; secondary explosives such as pentaerythritoltetranitrate(PETN), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), dynamite or trinitrotoluene (TNT), being more stable to mechanical shock and also more energetic; and tertiary explosives, such as ammonium nitrate fuel oil (ANFO) or ammonium nitrate aluminium powder (ANAL), the most stable explosives, requiring an intermediate explosive booster of secondary explosives to initiate.…”

“…For example, TNT was used in the Bali resort bombings in 2002; dynamite in the Madrid train station bombings in 2004; PETN in different attempts to blow up aircrafts in 2001 and 2009; and black powder-based IED in the Boston bombings in 2013em-ployed. [2] Thus, given the variety of explosives usable for terrorist attacks, it is evident that the analysis of all of them is of high relevance from a forensic standpoint.…”

“…For example, spectroscopic techniques have been successfully applied to a wide variety of samples and caseworks; readers interested on this issue can refer to a recent review. [2] Nevertheless, traditional separation techniques are still used for the analysis of explosives. Basically, the above-mentioned techniques allow the identification and quantification of many types of species, at very low concentrations.…”

Effect of periodicity in the optimization of fine tuned dipolar plasmonic structures for SERS

“…Different fabrication methods have been used for the development of these structures and in many cases they have been commercially available as reliable and relatively easy to use sensing devices [7][8][9][10] . Detecting small amounts of organic compounds using portable and fast devices has diverse applications in a wide range of fields such as security 11 , food safety 12 and environmental monitoring 13 . Although gold nanoparticles have lower enhancement values when compared to silver they are less prone to oxidation and show considerable robustness for use in plasmonic sensing 14 .…”