Analysis of TNT AND RDX on gauze wipes using the dtech test system


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MATRIX: Gauze Wipe


LIMIT OF DETECTION: TNT: 2.25 ug/100 cm2, RDX: 2.25 ug/100 cm2

This application describes a field screening method for determining TNT or RDX concentrations on gauze wipes. Acetone is used to extract the TNT or RDX from the gauze wipe and a chemical reaction is induced that causes a color change indicative of TNT or RDX in the sample. The TNT or RDX concentrations are estimated by comparison of the color development to a color card or reading of the relative reflectance with the DTECHTOR meter.

Extraction and analysis should be performed in a well ventilated area. Laboratory technicians should wear chemical resistant gloves and safety glasses. Use gloves during the entire procedure.

DTECH TNT Test Kit or DTECH RDX Test Kit. DTECH TNT or RDX Soil Extraction Pac. Gauze wipes. Equipment: DTECHTOR meter (optional).

Refer to the TNT or RDX Explosives Test Kit Instruciton Guide or TNT/RDX Soil
Extraction Pac Instruction Guide included in your test kit for detailed instructions.
1. Soak gauze wipe in acetone contained in extraction jar. Remove excess back into extraction jar. Wipe a 100cm2 (10 cm x 10 cm) surface area with the gauze wipe.
2. SDI can provide 100 cm2 wipe templates upon request (Part #1064000).
3. Place the 100 cm2 surface area wipe sample in Bottle 1 (in place of the 4.5g soil plug referred to in the TNT or RDX Soil Extraction Pac Instruction Guide) and extract as described in the extraction pac procedure.
4. Follow the soil sample procedure in the TNT or RDX Explosives Test Kit Instruction Guide to analyze samples.

Calculate the concentration in the wipe sample by using the color card supplied with the kit or the DTECHTOR and the table in the “Interpretation” section of the test kit instruction guide. To determine the wipe concentration in the wipe sample, the soil equivalents should be multiplied by 4.5 and expressed as ug/ 100 cm2.

The DTECH TNT and RDX test kits will also react to other similarly structured compounds. Please refer to the Specificity chart in the test kit instruction guide for detailed reactivities. Do not use reagents or components from one test kit with reagents or components from another. Do not use the test kits beyond the expiration date. Store at less than 80°F and run procedure out of direct sunlight.

EXPECTED RESULTS: See U.S. EPA SW-846 Methods 4050 and 4051 for TNT and RDX analysis in soil.

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