MAKING ENERGETIC MATERIALS SAFER

Abstract

Canine (K9) units and scientists developing explosives trace detection devices (ETDs) work with and are exposed to energetic materials when imprinting the dog or building instrument libraries. However, access to extremely hazardous materials, such as explosives, is limited, with a great need for training aids that provide a safe-handling and long shelf-life material. In order to address these needs, encapsulation of energetic materials, such as triacetone triperoxide (TATP), erythritol tetranitrate (ETN) and trinitrotoluene (TNT) in a polymer matrix have been developed, and extensively characterized to ensure explosive desensitization, controlled released, clean background odor and delivery of the pure explosive as effective training aids. Although, peroxide explosives, such as TATP and hexamethylene triperoxide diamine (HMTD) are a prominent threat, and their detection a priority within K9 units and ETD manufacturers, their absorption, distribution, metabolism and excretion (ADME) in the body have not been investigated. TATP is volatile and HMTD is lipophilic allowing for their inhalation and dermal absorption. Their distribution to the body was evaluated with blood incubations, which determined that TATP is stable for at least a week, while HMTD is degraded within minutes. Hepatic metabolism was investigated with microsomal and recombinant enzyme incubations. The metabolism of TATP undergoes hydroxylation catalyzed by cytochrome P450 2B6 (CYP2B6) to form TATP-OH, which undergoes glucuronidation catalyzed by uridine diphosphoglucuronosyltransferase 2B7 (UGT2B7) to form TATP-O-glucuronide, which was excreted in the urine of laboratory personnel and bomb-sniffing dogs exposed to TATP. Detection of these peroxide explosives and/or their metabolites in biological matrices (e.g. blood and urine) can be used as forensic evidence to exposure; therefore, paper spray ionization mass spectrometry was exploited as a robust analytical method for the analysis of peroxide explosives in in vitro and in vivo biological samples.