On-Site Analysis of Explosives in Soil: Evaluation of Thin-Layer Chromatography for Confirmation of Analyte Identity
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
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Two colorimetric-based methods are commonly used for on-site analysis of explosives in soil. For the TNT method, acetone soil extracts are reacted with base to produce reddish-colored Janowsky ions. For RDX, acetone extracts are acidified and reacted with zinc to reduce RDX to nitrous acid, and the nitrous acid is determined by reacting the resulting solution with a Griess reagent. The TNT method is subject to interference from the presence of other polynitroaromatic compounds such as TNB, tetryl, and the isomers of DNT. Likewise, the RDX method is interfered with by the presence of other nitramines such as HMX and tetryl, and organonitrate esters such as NG, PETN, and NC. This study investigates the use of thin-layer chromatography TLC as a simple on-site method to confirm the identity of analytes detected using colorimetric on-site methods. Separations using both laboratory-grade and locally available solvents were developed. The major limitation of this method is detection capability, which was estimated to be about 0.1 microgram of analyte. This corresponds to a concentration of 17 microgramsg when using 30 muL of spotting volume, or 500 microgramsg when using 1 muL of spotting volume.
- Inorganic Chemistry
- Organic Chemistry
- Ammunition and Explosives