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IDENTIFICATION OF ORGANIC EXPLOSIVES ON PLASTIC SURFACES
|Objective || |
To identify the explosive used, if any, to cause a bomb blast at the crime scene.
|Sample || |
Simulated bomb blast debris (plastic milk jug) containing trace amounts of organic explosives on its surface. Prepare the sample in the following way.
Place 20 drops of a mixture of explosives (0.25 2.0 µg/mL in acetonitrile) at random on one side of a plastic quart milk jug. Allow the acetonitrile to evaporate. Store the jug in a sealed plastic bag in the refrigerator until it will be processed.
|Reagents || |
Standard solutions, 1000 µg/mL in acetonitrile (e.g. from Cerilliant), for eight of the most important organic high explosives: HMX, RDX, nitroglycerin, PETN, Tetryl, TNT, 2,4-dinitrotoluene, 2-nitrotoluene.
Standard Reference Material
|Method || |
Solid phase extraction ; liquid chromatography
|Special equipment || |
Liquid chromatograph with C18 column and diode array detector ; 3-mL, polymeric reverse phase, solid phase extraction (SPE) cartridges (e.g. Oasis from Waters) ; vacuum manifold for SPE ; solvent evaporation system (heating block and a source of nitrogen); 2-mL chromatography vials with screw caps
|Procedure || |
For instructor (detailed); For student (brief)
|Typical results || |
Chromatograms of explosives standards and sample: 50 µL injection of liquid sample; C18 column; isocratic elution with 50:45:5 water:methanol:acetonitrile, flowing at 0.8 mL/min. UV spectra of RDX, Tetryl, and TNT. Typical results and discussion.