ANALYSIS OF EXPLOSIVES IN WATER BY CAPILLARY GAS-CHROMATOGRAPHY

A method has been developed for the quantitative analysis of water for low ppb levels of several explosive-type compounds. These include 2,4,6-TNT, tetryl, 2,4-DNT, and 2,6-DNT. The compounds are extracted from water with toluene and analyzed by capillary column gas chromatography with electron capture detection. Accuracy and precision of the method were studied in water spiked at the 1-, 10-, and 100-ppb levels; the average recoveries ranged between 96 and 103%. The developed method saves time and gives better recovery for dinitrotoluene analysis than EPA Method 625. A stability study of the compounds in water at pHs between 0.5 and 10 was performed over a 33-day period. Significant losses were found in water at greater than pH 6, with tetryl being the most affected and the dinitrotoluenes the least. The method can also be applied to the explosive RDX for qualitative purposes, but it is not suitable for quantitation due to poor extraction efficiency of RDX into toluene.