Method Development for the extraction of explosives from soil and subsequent analysis by DMA-MS

Abstract

Landmines are buried explosives charges used in military combat and pose an active threat to soldiers and civilians alike as they are hard to detect. One of method of detection is the detection of chemical signatures in the soil surrounding the buried landmine. Many of the chemical detection methods require a lengthy extraction and analysis of the explosives in the soil. The aim of this thesis is the development of a significantly faster extraction and analysis method of the analytes TNT, 2,4-DNT and 2-ADNT in soil with a DMA-MS in comparison to an established HPLC-MS method. For this, different extraction solvents were tested on different types of soil to determine a standard procedure. This method was then tested on various spiked soil samples in the respective concentration range of the HPLC-MS and DMA-MS and in a combined analysis with a long-term stability study of TNT in wet soil and real samples from a testing site. The chosen extraction method with HPLC-MS analysis proved to be very effective on all tested parameters, whereas the analysis with DMA-MS showed a trend towards lower recoveries and a greater degree of variation. The long-term study demonstrated that TNT degrades rapidly in wet soil due to biotransformation with ADNT as a product. The combination of the two techniques successfully detected TNT, DNT, and ADNT in the real samples. The DMA-MS offers a more sensitive response to TNT and 2,4-DNT and is better suited for a very quick detection at low concentrations. Due to instabilities in the DMAMS measurements however, the HPLC-MS is more appropriate for a quantitative analysis of explosives in soil.