Micro-differential thermal analysis detection of adsorbed explosive molecules using microfabricated bridges.

Although micromechanical sensors enable chemical vapor sensing with unprecedented sensitivity using variations in mass and stress, obtaining chemical selectivity using the micromechanical response still remains as a crucial challenge. Chemoselectivity in vapor detection using immobilized selective layers that rely on weak chemical interactions provides only partial selectivity. Here we show that the very low thermal mass of micromechanical sensors can be used to produce unique responses that can be used for achieving chemical selectivity without losing sensitivity or reversibility. We demonstrate that this method is capable of differentiating explosive vapors from nonexplosives and is additionally capable of differentiating individual explosive vapors such as trinitrotoluene, pentaerythritol tetranitrate, and cyclotrimethylenetrinitromine. This method, based on a microfabricated bridge with a programmable heating rate, produces unique and reproducible thermal response patterns within 50 ms that are characteristic to classes of adsorbed explosive molecules. We demonstrate that this micro-differential thermal analysis technique can selectively detect explosives, providing a method for fast direct detection with a limit of detection of 600x10(-12) g.

[1]  T. Thundat,et al.  Micro-differential thermal analysis detection of adsorbed explosive molecules using microfabricated bridges. , 2009, The Review of scientific instruments.

[2]  T. Thundat,et al.  Detection of adsorbed explosive molecules using thermal response of suspended microfabricated bridges , 2008 .

[3]  T. L. Wright,et al.  Electrical, Thermal, and Mechanical Characterization of Silicon Microcantilever Heaters , 2006, Journal of Microelectromechanical Systems.

[4]  Panos G. Datskos,et al.  Analyte species and concentration identification using differentially functionalized microcantilever arrays and artificial neural networks , 2006 .

[5]  Shiv k. Sharma,et al.  Portable remote Raman system for monitoring hydrocarbon, gas hydrates and explosives in the environment. , 2005, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[6]  D. Walt.  Electronic Noses: Wake Up and Smell the Coffee , 2005 .

[7]  Panos G. Datskos,et al.  Response Signatures for Nanostructured, Optically-Probed, Functionalized Microcantilever Sensing Arrays , 2004 .

[8]  T. Thundat,et al.  Detection of trinitrotoluene via deflagration on a microcantilever , 2004 .

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

[10]  T. Thundat,et al.  Adsorption of trinitrotoluene on uncoated silicon microcantilever surfaces. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[11]  B. Rogers,et al.  Explosives: A microsensor for trinitrotoluene vapour , 2003, Nature.

[12]  T. Thundat,et al.  Sensitive detection of plastic explosives with self-assembled monolayer-coated microcantilevers , 2003 .

[13]  Chia-Jung Lu,et al.  Portable gas chromatograph with tunable retention and sensor array detection for determination of complex vapor mixtures. , 2003, Analytical chemistry.

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

[15]  Richard J. Colton,et al.  Making the World a Safer Place , 2003, Science.

[16]  S F Hallowell,et al.  Screening people for illicit substances: a survey of current portal technology. , 2001, Talanta.

[17]  R. Masel.  Principles of Adsorption and Reaction on Solid Surfaces , 1996 .

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

[19]  R. T. Chamberlain,et al.  Experimental and Theoretical Demonstration of the Interfacial Interaction Potential Between an Adsorbed Film and a Smooth Substrate , 2000 .

[20]  Herbert H. Hill,et al.  Capabilities and limitations of ion mobility spectrometry for field screening applications , 1997 .