An explosive study
My sister Swathi Murali has her first peer-reviewed paper out, expected in print in the December 2026 edition of Forensic Chemistry. Excerpt from the abstract:
Electrical tapes may be submitted to forensic laboratories for analysis concerning their utilization in the construction of improvised explosive devices (IEDs). However, post-blast tape specimens collected at an explosion site are seldom pristine and may undergo physical and chemical alterations that can affect the outcome of a forensic examination. Therefore, a systematic assessment of the impact of detonation on the analysis and comparison of tapes was conducted on a selection of 30 black vinyl electrical tapes from brands representative of the US market, which were subjected to controlled detonations.
Swathi and her coauthor Patrick Buzzini, who is her PhD advisor at the Sam Houston State University in Texas, then tested the tapes using three techniques. The first, Fourier-transform infrared spectroscopy (FTIR), identifies materials based on how they absorb infrared light. However, Swathi found it was easily confused by the explosions, with residues from TNT and the blasting cap and the heat introducing noise. Second, energy-dispersive X-ray spectroscopy (EDS) — which identifies elements a sample has by studying the X-rays it emits when blasted with electrons — similarly suffered from noise in the data because post-blast fragments often acquired aluminium and silicon from components of the explosive setup. Finally, she found gas chromatography-mass spectrometry (GC-MS) to be the most reliable because it isolated the tape’s compounds first before identifying them, and could thus tell apart the tape’s plasticisers from contaminants introduced by the blast.
(I’ve never seen any of these instruments up close. However, I’ve often had to write about and/or discuss GC-MS in the context of drug quality. Based on that plus some reading, I know FTIR is the cheapest and easiest to run of the techniques whereas both EDS and GC-MS are more expensive and more labour-intensive, and their operators also need skills likely to be more costly to acquire. The paucity of GC-MS setups in poorly funded Indian drug-testing labs is an important reason why their ability to test the purity of various drugs is constrained, though I reckon the country’s forensic labs are better off.)
Congratulations, Swathi!
