GC-TEA
Definition
Gas chromatography with a Thermal Energy Analyser. Pyrolytic cleavage of the nitro group to NO followed by chemiluminescent reaction with ozone. Nitro-specific, sub-nanogram sensitivity.
- Full name
- Gas chromatography with Thermal Energy Analyser
- Mechanism
- Pyrolytic cleavage of nitro group to NO, then chemiluminescence with ozone
- Selectivity
- Nitro-specific
- Sensitivity
- Sub-nanogram
Common questions
Why is nitro-group specificity valuable in explosives residue analysis?+
Post-blast debris contains an enormous background of combustion byproducts and environmental compounds, and a detector that responds only to nitro-containing molecules filters out that background almost entirely, letting trace nitrate ester or nitroaromatic explosive residues stand out clearly.
How does GC-TEA compare to GC-MS for explosives trace detection?+
GC-TEA offers much lower detection limits and higher selectivity specifically for nitro compounds at sub-nanogram levels, while GC-MS provides broader structural confirmation across many compound classes, so laboratories often use TEA for sensitive screening and MS for confirmatory identification.
What happens to compounds without a nitro group in a GC-TEA analysis?+
They do not generate the NO needed for the chemiluminescent reaction with ozone, so they produce little or no signal, which is precisely what gives the method its selectivity but also means it will miss non-nitro explosive compounds entirely.
Related terms
- Diphenylamine Test
- Color test for nitrates and nitro groups. Diphenylamine in conc. H2SO4 turns deep blue with oxidising NO3-/NO2-. Also a primer-residue test, which...
- IMS
- Ion Mobility Spectrometry. Drift-tube separation of gas-phase ions at ambient pressure. Smiths IONSCAN 500DT and Sabre 5000 give 5-second field screening on...
- Ion Chromatography (IC)
- An analytical technique that separates and quantifies anions and cations in solution. In post-blast residue analysis, IC detects nitrate, nitrite, ammonium, and...
- Janowski Test
- Color test for nitroaromatics. Sample plus DMSO plus alcoholic KOH gives a violet Meisenheimer complex. Positive for TNT, picric acid, tetryl and...
- Modified Griess Test
- A contact-transfer colour chemistry test for nitrite-containing propellant combustion residue. Sulphanilic acid undergoes diazotisation with nitrous acid (from NO2 on the target...
- Post-Blast Residue (PBR)
- Unconsumed explosive plus reaction by-products left at the seat of an explosion, on debris, on fragments and on the hands or clothing...
- VBIED
- Vehicle-Borne Improvised Explosive Device. Pulwama 2019 is the recent Indian reference case (RDX plus ammonium nitrate).