The effect of soil type on the extraction of insensitive high explosive constituents using four conventional methods

Abstract

Explosive contamination is commonly found at military and manufacturing sites [1][2][3]. Under current environmental legislation the extent of the contamination must be characterized by soil sampling and subsequent separation of the explosive contaminants from the soil matrix by extraction to enable chemical analysis and quantification [4]. It is essential that the extraction method can consistently recover explosive residue from a variety of soil types i.e. all materials that have not degraded or irreversibly bound to the matrix, so that any resultant risk is not underestimated. In this study, five different soil types with a range of organic content, particle size and pH, were spiked with a mixture of RDX, DNAN, NQ and NTO at 50 mg/kg and were extracted using one of four one-step extraction methods: stirring, shaking, sonication, and accelerated solvent extraction (ASE). Analysis of the extraction efficiencies of the four methods found that they were broadly successful for the extraction of all IHE constituents from all five soils (an average of 84% ± 14% recovery across 80 extractions). However, soils with high organic content (Total Organic Content (TOC) ≥ 2%) were found to significantly affect . Please refer to any applicable publisher terms of use. extraction efficiency and reproducibility. NTO and DNAN were the least consistent in extraction efficiency with poorest recovery of NTO as low as 37% ± 2%. Of the four tested methods shaking was found to be the most reproducible, though less efficient than stirring (64%-91%). ASE was found to have the most variable results for extraction of IHE constituents suggesting that ASE was the most affected by the different soil types. Therefore, it is recommended that the efficiency and reproducibility of the selected extraction method should be validated by extracting known concentrations of the IHE from the soil of interest and that any required correction factors are reported.

Abiotic reduction of 3-nitro-1,2,4-triazol-5-one (NTO) and other munitions constituents by wood-derived biochar through its rechargeable electron storage capacity

“…NTO, NQ, and daughter products were extracted with a 3 : 7 (v/v) mixture of acetonitrile and 0.1% trifluoroacetic acid, whereas DNAN, RDX, and daughter products were extracted with an 8 : 2 mixture of acetonitrile and 0.1% trifluoroacetic acid. 47 Each biochar sample was extracted three times. Samples of MCs and daughter products from multiple extractions were combined to obtain the total recovery.…”

Quantitative Environmental Assessment of Explosive Residues from the Detonation of Insensitive High Explosive Filled 155 mm Artillery Shell

“…Sub-samples were extracted with acetonitrile/water (1 : 1) (40 mL) by shaking for 18 hours at 180 rpm in amber glass vials [41]. Samples were left to stand for 30 minutes before filtration through a 0.2 μm PES filter and analyzed by HPLC.…”

Environmental analysis of aqueous 3-nitro-1,2,4-triazol-5-one (NTO) by ion chromatography with conductivity detection

“…Soils for energetics analysis are commonly extracted with an organic solvent (i.e., acetonitrile) prior to analysis due to the hydrophobic character of conventional energetic compounds (US EPA 2006). However, NTO extraction recoveries from soils by using just acetonitrile are less than 60% (Temple et al 2019). The hydrophilic nature of NTO, as well as another IHE compound, nitroguanidine, has prompted the development of alternative soil extractions involving an acidified aqueous (Felt et al 2016) or partially aqueous stage (Crouch et al 2020;Temple et al 2019).…”

“…However, NTO extraction recoveries from soils by using just acetonitrile are less than 60% (Temple et al 2019). The hydrophilic nature of NTO, as well as another IHE compound, nitroguanidine, has prompted the development of alternative soil extractions involving an acidified aqueous (Felt et al 2016) or partially aqueous stage (Crouch et al 2020;Temple et al 2019). The efficient recovery of NTO with a simple DI extraction from all of the spiked soils, which had wide-ranging organic content (<250 to 15,000 mg/kg total organic carbon) and particle size (12% to 100% fines), likely reflects both NTO's high water solubility and the spike delivery as a solution.…”