Development of High Volume Sampling Man-Portable Explosives Detection Systems

Many explosives detection applications require portable detection systems that can be moved rapidly from one location to another. Explosives sniffing canines are excellent “portable sensors” in many respects, but they also have drawbacks, including high maintenance requirements, lack of 24/7 operability, and inability to identify the specific type of explosive that is detected. For these reasons, there is interest in the development of man-portable explosives detection equipment that can be used to replace or supplement canines in some situations. In the past few years, notable progress has been made in the development of hand-held systems employing ion mobility spectrometry (IMS).While commercially available systems of this type have high sensitivity to a number of explosives, they are adapted primarily for swipe sampling, where a particulate sample is collected via physical contact with a sampling pad and then introduced to the detector.These systems have low air sampling rates on the order of 1- 2 liters per minute, which is disadvantageous in many real world applications where collection of vapor or air borne particulate material is required. In this paper, we discuss the development of integrated man-portable detection systems that combine a commercial man-portable IMS detector with a miniaturized version of a patented chemical preconcentrator developed at Sandia National Laboratories. Attaching the front-end preconcentrator to the detector allows air sampling rates to be increased by a factor of 60 or more, greatly facilitating air borne sample collection.We discuss the design and optimization of the preconcentrator, and present results obtained in the collection of explosives such as 2, 3, 6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX).Work currently in progress includes the extension of the use of the preconcentrator to other classes of compounds such as drugs, and efforts aimed at commercialization.