Development of Microfluidic Paper-Based Analytical Devices for the Detection of Low Explosives

Abstract

Incidents of terrorism have been on the rise despite increased government regulation of explosives. These regulations and the internet have made the application of improvised explosive devices (IEDs) such as fireworks and smokeless powders more prevalent. These devices contain low explosives which are easier to acquire than high explosives, which are more closely monitored. Pipe bombs typically contain smokeless powders, which are mostly comprised of energetics such as nitroglycerine (NG) and organic additives such as diphenylamine. Another type of easily obtainable material containing low explosives is pyrotechnics. Pyrotechnics are usually made up of a mixture of inorganic chemical oxidizers and carbon, sulfur, or metal fuels that are used to produce different types of sound and lighting effects. Due to the wide range of compounds contained in IEDs, it makes detection difficult and time consuming as many different methods must be used to determine composition. This research project worked to develop a method for the rapid detection of a variety of low explosive components. Through the use of microfluidic paper-based analytical devices (μPADs), tests can be performed for multiple compounds simultaneously via colorimetric reactions. The first of the two μPADs was developed for the detection of inorganic compounds commonly contained in low explosives, such as pyrotechnics. The second device was developed for the detection of energetics and organic additives contained within smokeless powders. Visual limits of detection ranged from 0.025-0.5 μg of the target compounds with an analysis time of less than 10 minutes for both devices. These methods allow for rapid, on-site detection of a range of different low explosives from pyrotechnics to smokeless powders.