Spectroscopic Ultra-Trace Detection of Nitroaromatic Gas Vapor on Rationally Designed Two-Dimensional Nanoparticle Cluster Arrays

J. Wang, L. Yang, S. Boriskina, B. Yan, B.M. Reinhard
Boston University, US

Keywords: nanoparticle cluster arrays, surface enhanced Raman spectroscopy, 2, 4-dinitrotoluene, explosive detection

Summary:

Nitroaromatic explosives are components of several widely used explosives, and there is an acute need for reliable and fieldable sensors that facilitate a rapid detection of their sublimated vapor at low concentrations in the gas phase. Nanoparticle cluster arrays (NCAs) are engineered two-dimensional plasmonic arrays which utilize the E-field focusing effect in nanoparticle clusters of well defined size, self-assembled at pre-defined locations, to generate high and reproducible surface enhanced Raman spectroscopy (SERS) signal enhancements. NCAs are reliable platforms for critical sensing applications through providing high signal enhancements from small molecules and entire bacterial cells drop-coated on the NCAs. In this work we demonstrate that rationally designed NCAs are capable of detecting ultra-traces of 2,4-dinitrotoluene (DNT) vapor. NCAs facilitated the detection of DNT vapor at a concentration of at least 10 ppt, even in the presence of an excess of potential interferents, including Diesel fuel, fertilizers, and pesticides. The SERS signal intensity of DNT showed a continuous response over the entire monitored concentration range (10 ppt - 100 ppb). The small size, superb sensitivity and selectivity, as well as the fast response time of < 5 min make NCAs a valuable photonic sensor platform for ultra-trace nitroaromatic gas vapor detection.