Direct detection and speciation of trace explosives using a nanoporous multifunctional microcantilever.

We have developed a highly selective and sensitive nanomechanical infrared (IR) calorimetric spectrometer for use in the direct detection of ultralow concentrations of explosive vapors using a nanoporous TiO2 cantilever. These cantilevers were fabricated using a two-step anodization and photolithography process. By patterning nanoscale wells onto a cantilever, its surface area is increased by 2 orders of magnitude and the surface is converted into a preconcentrator. Resonant excitation of adsorbed molecules using IR radiation causes the cantilever to bend due to temperature changes originating from the nonradiative decay process. The porous structure of the cantilever increases its thermomechanical sensitivity as well as the number of adsorbed molecules. The system performance was demonstrated by detecting binary explosive mixtures under ambient conditions. The TiO2 sensor surface also allows regeneration through the photocatalytic decomposition of adsorbates under UV irradiation.

[1]  J. Yinon,et al.  Peer Reviewed: Detection of Explosives by Electronic Noses , 2003 .

[2]  Panos G. Datskos,et al.  Chemical detection based on adsorption-induced and photoinduced stresses in microelectromechanical systems devices , 2001 .

[3]  Jing Wang,et al.  Spectroscopic ultra-trace detection of nitroaromatic gas vapor on rationally designed two-dimensional nanoparticle cluster arrays. , 2011, Analytical chemistry.

[4]  Nelly Piazzon,et al.  Bio-inspired nanostructured sensor for the detection of ultralow concentrations of explosives. , 2012, Angewandte Chemie.

[5]  Andreas Hierlemann,et al.  Evaluation of multitransducer arrays for the determination of organic vapor mixtures. , 2008, Analytical chemistry.

[6]  F. Pristera,et al.  ANALYSIS OF EXPLOSIVES BY INFRARED SPECTROSCOPY , 1960 .

[7]  Arun Majumdar,et al.  Optimization and performance of high-resolution micro-optomechanical thermal sensors , 1997 .

[8]  Panos G. Datskos,et al.  Photomechanical chemical microsensors , 2001 .

[9]  S. Martin,et al.  Environmental Applications of Semiconductor Photocatalysis , 1995 .

[10]  A Fainberg,et al.  Explosives Detection for Aviation Security , 1992, Science.

[11]  Thomas Thundat,et al.  Trace explosive detection using photothermal deflection spectroscopy , 2008 .

[12]  T. Thundat,et al.  Desorption characteristics of uncoated silicon microcantilever surfaces for explosive and common nonexplosive vapors. , 2004, Ultramicroscopy.

[13]  Kim Ts,et al.  Degradation kinetics and mechanism of RDX and HMX in TiO2 photocatalysis. , 2006 .

[14]  B. Clowers,et al.  Direct real-time detection of RDX vapors under ambient conditions. , 2013, Analytical chemistry.

[15]  Sangmin Jeon,et al.  Molecular recognition using receptor-free nanomechanical infrared spectroscopy based on a quantum cascade laser , 2013, Scientific Reports.

[16]  Larry W. Burggraf,et al.  Photothermal spectroscopy using multilayer cantilever for chemical detection , 2000 .

[17]  Peter Kolla,et al.  The Application of Analytical Methods to the Detection of Hidden Explosives and Explosive Devices , 1997 .

[18]  Kun-Hong Lee,et al.  Microcantilevers with nanowells as moisture sensors , 2009 .

[19]  Jincai Zhao,et al.  Detection of explosives with a fluorescent nanofibril film. , 2007, Journal of the American Chemical Society.

[20]  Henric Östmark,et al.  Vapor Pressure of Explosives: A Critical Review , 2012 .

[21]  I. R. Lewis,et al.  Interpretation of Raman Spectra of Nitro-Containing Explosive Materials. Part I: Group Frequency and Structural Class Membership , 1997 .

[22]  Karine Bonnot,et al.  Tunable generation and adsorption of energetic compounds in the vapor phase at trace levels: a tool for testing and developing sensitive and selective substrates for explosive detection. , 2010, Analytical chemistry.

[23]  D. Moore.  Instrumentation for trace detection of high explosives , 2004 .

[24]  J. Yates,et al.  Photocatalysis on TiO2 Surfaces: Principles, Mechanisms, and Selected Results , 1995 .

[25]  E. Zellers,et al.  Limits of recognition for simple vapor mixtures determined with a microsensor array. , 2004, Analytical chemistry.

[26]  J. K. Gimzewski,et al.  Photothermal spectroscopy with femtojoule sensitivity using a micromechanical device , 1994, Nature.

[27]  Jinwoo Lee,et al.  Enhanced photocatalytic activity of highly crystallized and ordered mesoporous titanium oxide measured by silicon resonators. , 2010, Analytical chemistry.

[28]  Y. Liu,et al.  TiO2 Nanotubes with Tunable Morphology, Diameter, and Length: Synthesis and Photo-Electrical/Catalytic Performance , 2009 .

[29]  Trisha L. Andrew,et al.  Detection of explosives via photolytic cleavage of nitroesters and nitramines. , 2011, The Journal of organic chemistry.