Enhanced electrospray ionization mass spectrometric detection of hexamethylene triperoxide diamine (HMTD) after oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD).

Tomasz Krawczyk

Index: Rapid Commun. Mass Spectrom. 29 , 2257-62, (2015)

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Abstract

Hexamethylene triperoxide diamine (HMTD) is one of the peroxide-based explosives that are difficult to detect using standard analytical methodologies.It was analyzed by electrospray ionization mass spectrometry (ESI-MS) on a UPLC-TOF instrument. Alkali metal salts were used to promote the formation of ions.In the full scan positive ion mode a 3 ng (13 pmol) limit of detection was achieved if [HMTD + Me](+) ions (Me = Li, Na, K) were detected. It was found that HMTD easily undergoes oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD) in the source as well as in the samples. TMDDD can be detected as [TMDDD + Me](+) ions, but better ionization efficiency leads to the detection limit of TMDDD at the 2 pg (0.01 pmol) level. In butyl acetate the yield of oxidation of HMTD to TMDDD reaches 25% within 20 min at 120 °C, which offers a simple way of improving the detection limit of HMTD by two orders of magnitude.A simple procedure of detection of HMTD that matches the most sensitive methods available was developed. It uses standard equipment available in many laboratories. It was shown that the frequently reported [HMTD-H](+) cation observed by various authors was in fact a misinterpretation of the results, and should be attributed to [TMDDD + H](+).Copyright © 2015 John Wiley & Sons, Ltd.