An extraction/concentration procedure for analysis of low-level explosives in soils

The methods traditionally used for explosives analysis in soil matrices have inherent data quality limitations for low-level samples. The traditional methods employ a soil-dilution extraction of the sample prior to analysis by high performance liquid chromatography with UV absorption detection. Another concern with the traditional analysis is that energetics contamination in environmental samples is often very heterogeneous in nature, usually requiring a large number of samples and multiple testing. The technique presented here addresses these data quality limitations by using a concentrative extraction procedure which produces a small volume of extract from a large soil sample. A concentration factor of 60-fold is achieved in this manner and energetics detection limits for soils are lowered by two orders of magnitude. The larger soil sample size also helps reduce the error associated with sample heterogeneity. The ability to detect explosive-based contaminants at levels of environmental interest enables a more accurate assessment of the transport pathways and treatment options for explosives contamination.