A Colorimetric Sensor Array for Detection of Triacetone Triperoxide Vapor

Abstract

Triacetone triperoxide (TATP), one of the most dangerous primary explosives, has emerged as an explosive of choice for terrorists in recent years. Owing to the lack of UV absorbance, fluorescence, or facile ionization, TATP is extremely difficult to detect directly. Techniques that are able to detect generally require expensive instrumentation, need extensive sample preparation, or cannot detect TATP in the gas phase. Here we report a simple and highly sensitive colorimetric sensor for the detection of TATP vapor with semiquantitative analysis from 50 ppb to 10 ppm. By using a solid acid catalyst to pretreat a gas stream, we have discovered that a colorimetric sensor array of redox sensitive dyes can detect even very low levels of TATP vapor from its acid decomposition products (e.g., H 2 O 2 ) with limits of detection (LOD) below 2 ppb (i.e., <0.02% of its saturation vapor pressure). Common potential interferences (e.g., humidity, personal hygiene products, perfume, laundry supplies, volatile organic compounds, etc.) do not generate an array response, and the array can also differentiate TATP from other chemical oxidants (e.g., hydrogen peroxide, bleach, tert-butylhydroperoxide, peracetic acid).Triacetone triperoxide (TATP), a high-powered primary explosive first synthesized in 1895, 1 has become well-known during the past decade as an explosive of choice for terrorists. 2 Due to its extreme sensitivity, TATP does not have any practical engineering or military applications. It has been used, however, in at least three major terrorist acts in the past 10 years, 2b in part because TATP is easy to prepare from readily available chemicals (i.e., acid catalyzed reaction of acetone with hydrogen peroxide) 3 but difficult to detect. 4 While several techniques for TATP detection have been developed in recent years 5 and there are several commercial products available, 6 these methods generally require expensive and generally nonportable instrumentation, 7 need extensive sample preparation, 8 are qualitative or have poor limits of detection, 5 or are limited to liquid or solid samples and cannot detect TATP vapor. 9 Hence, the development of an inexpensive, portable, and easy-to-use device for the field detection of TATP remains a high priority. Particularly, on-site detection of TATP vapor would have significant advantages for rapid screening.In recent years, our group has developed a colorimetric sensor array methodology 10 that has been applied successfully for the identification of a wide range both of toxic industrial gases and vapors 11 and of organic analytes in aqueous liquids. 12 Herein, we describe a colorimetric sensor array for the sensitive and selective detection of the vapor phase of TATP. Owing to the lack of UV absorbance, fluorescence, or facile ionization, TATP is extremely difficult to detect directly: indeed, even redox sensitive dyes are not very responsive to TATP vapor. By using a solid acid catalyst to pretreat a gas stream, we have discovered that a colorimetric sensor array can dete...

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