The detection and quantification of trace amounts of hexamethylenetriperoxidediamine (HMTD), a primary organic peroxide explosive, is investigated by LC/MS. LC/MS is well suited to the analysis of explosive compounds, such as HMTD, that are thermally labile. This property of HMTD has prevented other chromatography separation techniques, such as GC/MS, from being successfully employed for the analysis of HMTD. In this paper, the development of an LC/MS method capable of detecting trace quantities of HMTD is described. Potentially, the method is capable of being used to detect a lower detection limit of 20 pg µl 21 (2 ng per 100 µl) of HMTD. In comparison to other chromatography separation techniques that are used for analysis of explosives and explosive mixtures, e.g. GC/MS and GC/TEA, this represents an extremely valuable technique. † JCrown copyright 2001/DSTL -published with the permission of the Controller of Her Majesty's Stationery Office. Fig. 1 Molecular structures for HMTD proposed by (a) Baeyer and Villiger (1900) and (b) Grisewald and Siegens (1921).

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The first comprehensive assessment of 34 solid phase extraction sorbents is presented for organic explosive residues in wastewater prior to analysis with liquid chromatography-high resolution accurate mass spectrometry (LC-HRMS). A total of 18 explosives were selected including nitramines, nitrate esters, nitroaromatics and organic peroxides. Three polymeric divinylbenzene-based sorbents were found to be most suitable and one co-polymerised with n-vinyl pyrrolidone offered satisfactory recoveries for 14 compounds in fortified wastewater (77-124%). Limits of detection in matrix ranged from 0.026-23μgL with R≥0.98 for most compounds. The method was applied to eight 24-h composite wastewater samples from a London wastewater works and one compound, 2,4-dinitrotoluene, was determined over five days between 332 and 468g day (225-303ngL). To further exploit the suspect screening capability, 17 additional explosives, precursors and transformation products were screened in spiked wastewater samples. Of these, 14 were detected with recoveries from 62 to 92%, highlighting the broad applicability of the method. To our knowledge, this represents the first screen of explosives-related compounds in wastewater from a major European city. This method also allows post-analysis detection of new or emerging compounds using full-scan HRMS datasets to potentially identify and locate illegal manufacture of explosives via wastewater analysis.

We report four new electronic transitions of the SrOH free radical, the C̃ 2∏–X̃ 2∑+, D̃ 2∑+–X̃ 2∑+, Ẽ 2∑+–X̃ 2∑+, and F̃ 2∏–X̃ 2∑+ transitions. SrOH was prepared in a supersonic jet by laser ablation and spectra were recorded using laser-induced fluorescence. The C̃ 2∏–X̃ 2∑+ excitation spectrum shows complex vibronic structure which is attributed, at least in part, to Renner–Teller activity in the excited electronic state. This is supported by dispersed fluorescence spectra which show substantial bending mode activity in the emission from several different excited vibronic levels. It is suggested that the prominence of nominally forbidden vibrational features arises from a large change in permanent electric dipole moment between the X̃ and C̃ states. In turn, this suggests that the C̃ 2∏ state of SrOH is the analogue of the “reverse-polarized” ∏ states known for the alkaline-earth monohalides, i.e., the highest occupied π orbital points towards the O atom. The D̃ 2∑+–X̃ 2∑+, Ẽ 2∑+–X̃ 2∑+, and F̃ 2∏–X̃ 2∑+ spectra are much simpler than the C̃–X̃ system, being dominated by regular structure in the Sr–O stretching vibration.

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