J-Acid Test (Janovsky-Type)
Definition
A presumptive colour test for polynitroaromatic compounds (TNT, DNT) that produces a red-purple coloration. More selective for nitroaromatics than the Griess or DPA tests.
- Target analytes
- Polynitroaromatic compounds
- Examples detected
- TNT, DNT
- Positive result
- Red-purple coloration
- Selectivity
- More selective than Griess or DPA for nitroaromatics
Common questions
Why would an examiner choose the J-acid test over the Griess test?+
The Griess test targets nitrite and nitrate residues broadly and is prone to false positives from other nitrogen-containing sources, while the J-acid (Janovsky-type) test reacts more specifically with nitroaromatic ring structures, making it a useful confirmatory or discriminating presumptive step for TNT-class compounds.
Does a positive J-acid result confirm the specific explosive present?+
No. Like other presumptive colour tests, a positive result only indicates the likely presence of a polynitroaromatic compound. Confirmation of the specific compound still requires instrumental analysis such as GC-MS or LC-MS.
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