RUI: Addressing critical challenges in trace explosives detection through fundamental research in electrochemical science

Washington State University, Pullman WA

Investigators

Abstract

Abstract : Addressing the existing deficiencies in trace explosives detection through fundamental research in electrochemical science Non-Technical: Terrorists today are using a diverse palette of threats. There is no single technology that can detect a wide variety of explosives. The goal of this research is to address existing deficiencies in trace explosives detection such as high detector cost, low sensitivity, susceptibility to interferences and high detection limits by investigating a promising electrochemical sensor technology. The research objective is to enhance the performance of the promising electrochemical sensor technology by understanding how explosive vapors react with sensors while engineering the sensor device architecture to meet the rigorous sensitivity and selectivity demands in field conditions. A two-order-of-magnitude reduction in detector cost as compared to existing screening systems in airports such as Smiths IONSCAN is envisioned. The approach of using a new signal conditioning technique to concurrently improve sensitivity and selectivity in explosives detection is poised to transform current practices in augmenting electrochemical sensor performance. An unknown but probably large number of civilian users will benefit from the knowledge of screening threats. The proposed research will enable security forces (civilian, military, industrial) to have inexpensive detectors for instant, on-the-spot screening of suspicious substances or trace detection from a surface sampling. Broader uses are easy to envision - e.g., citizen involvement in widespread air quality monitoring using the proposed low-cost electrochemical gas sensors. A cohesive outreach plan with three major thrusts is planned as part of this research: summer camp for high school students, teacher training workshop, and job training for veterans. Technical: The goal of this research is to solve critical barriers such as high detector cost, low sensitivity, susceptibility to interferences, and high detection limits impeding trace detection and robust discrimination of explosives in field conditions. A mixed potential based electrochemical gas sensing mechanism is envisioned to address the current challenges in explosives detection. The research objective is to investigate the sensor-analyte interaction and engineer the electrochemical interface to augment the sensitivity and selectivity while lowering the detection limit and cost in screening explosives under field conditions. The approach is to (a) theoretically understand the thermal decomposition of the analyte to improve the limits of detection; (b) study heterogeneous gas phase catalysis to improve the sensitivity; (c) explore a novel signal conditioning technique to improve the sensitivity and selectivity amidst strong interference; (d) investigate unique electrochemical signature to impart the required selectivity; (e) implement low-cost paper based sensor platform to minimize detector cost; and (f) independently validate the test results and pursue field testing at Portland International Airport. The approach of using a new signal conditioning technique to concurrently improve sensitivity and selectivity in explosives detection is poised to transform current practices in augmenting electrochemical sensor performance. Implementing a paper based explosive sensor platform will pave the way for a new generation of electrochemical sensors. The research results might lead to a breakthrough in explosives screening with potential detection limits of parts per trillion (pg/mL), a 1000:1 specificity (out of every 1000 positive IDs, 1 is false), and an estimated two-order magnitude reduction in detector cost all as compared to the gold standard Gas Chromatography-Mass Spectrometry detector systems. The research results will be a quantum leap in the implementation of simple and inexpensive detectors for instant, on-the-spot screening of suspicious substances vital to a vast number of anticipated users.