Investigation of Isotopic Linkages between Precursor Materials and the Improvised High Explosive Product Hexamethylene Triperoxide Diamine

Abstract

The results of isotope ratio mass spectrometry (IRMS) on hexamethylene triperoxide diamine (HMTD) and its precursor hexamethylenetetramine (hexamine) is presented. HMTD was prepared from hexamine using several different sources of hexamine under both controlled laboratory conditions and in field experiments that represent the less controlled conditions that are likely to be observed in forensic casework scenarios. Precursor and product carbon isotope δ values consistently fit a linear relationship regardless of precursor or conditions. The magnitude of the isotope fractionation observed is affected by the efficiency of the reaction, with greater yielding reactions giving rise to HMTD with δ values more similar to the precursor material than lower yielding reactions. Nitrogen isotope δ values comparing precursor with product show some linearity when the reaction conditions are carefully controlled; however, results indicate a poor fit with linearity when synthesis conditions are more variable. Despite the greater variation, the HMTD product consistently has a more positive δ value compared with the hexamine precursor. The results observed from these experiments suggest hexamine reacts to form HMTD in a 1:1 ratio. Having prepared multiple HMTD samples from various precursors using a range of experimental conditions, we have observed results that may be useful in forensic investigations of improvised explosive materials.

The Potential of Isotope Ratio Mass Spectrometry (IRMS) and Gas Chromatography‐IRMS Analysis of Triacetone Triperoxide in Forensic Explosives Investigations

“…Extrapolation to complete conversion shows the validity of this linear correlation as the resulting value is indeed close to the δ 13 C value of the precursor. A similar carbon isotope trend has been observed by Lock et al for the explosive HMTD. In our study, a short reaction time has been chosen out of safety consideration.…”

“…The preliminary study on TATP showed that TATP samples were distinguishable using the carbon and hydrogen isotopic compositions. In addition, Lock et al focused on the linkage of explosives to its precursors. A relationship was observed between the explosives RDX and HMTD, and their precursor hexamine for both carbon and nitrogen isotope ratios.…”

Gas‐phase reactions of alcohols with hexamethylene triperoxide diamine (HMTD) under atmospheric pressure chemical ionization conditions

“…Ring strain in HMTD may account for the stability and sensitivity issues mentioned above. Despite a plethora of information on HMTD, a mechanism for its formation has only recently been tentatively proposed …”

Locating bomb factories by detecting hydrogen peroxide

“…Finally Lazarowski and Dorman studied the capability of trained detection dogs to correctly signal the presence of one or more explosive mixtures containing potassium chlorate [11]. In addition, some authors have evaluated an isotopic analysis application to study a possible association between precursors used as starting material and explosive products obtained [12][13][14][15].…”