TY - JOUR
T1 - The potential for and challenges of detecting chemical hazards with temperature-programmed microsensors
AU - Meier, D. C.
AU - Evju, J. K.
AU - Boger, Z.
AU - Raman, B.
AU - Benkstein, K. D.
AU - Martinez, C. J.
AU - Montgomery, C. B.
AU - Semancik, S.
N1 - Funding Information:
We acknowledge the contributions from the staff of the Edgewood Chemical Biological Center (ECBC), particularly those of Michael Ellzy and J. Michael Lochner, in the CWA detection experiments. We also acknowledge technical support from Michael J. Carrier and James D. Melvin at NIST. Financial support for this work was provided by the Department of Homeland Security (DHS-HSARPA), the Defense Threat Reduction Agency (DTRA), the Department of Defense (DoD), and a Postdoctoral Research Associateship from the National Research Council (NIST-NIH-NRC).
PY - 2007/1/30
Y1 - 2007/1/30
N2 - Several recent demonstrations of the abilities of micro-electromechanical systems (MEMS)-based microsensor technology to detect hazardous compounds and their simulants in a variety of background conditions are presented. In each case, two pairs of conductometric metal oxide sensors (TiO2 and SnO2) produced via chemical vapor deposition are operated using temperature-programmed sensing (TPS). NIST microdevices can utilize this operating mode to sample a wide operating temperature range (50 °C-480 °C) in a very short time (<15 s). The voluminous databases generated by this method can be analyzed using signal processing techniques, such as artificial neural networks (ANNs), to provide actionable outputs. Several examples are presented: cyclohexyl methyl methylphosphonate (CMMP), a simulant for cyclosarin (GF), is detected at concentrations ranging from 700 pmol/mol to 90 nmol/mol in air backgrounds ranging from 0% relative humidity (RH) to 70% RH. The chemical warfare agents (CWAs) tabun (GA), sarin (GB), and sulfur mustard (HD) are detected at 25 nmol/mol in dry air, humidified air (40% RH), and diesel fume-laden air (3.5% saturation). Finally, a selection of five toxic industrial chemicals (TICs) and one chemical warfare simulant (CWS) are measured at immediate danger to life and health (IDLH) and permissible exposure limit (PEL) levels in an array of backgrounds, including seven different interferences, each at three concentration levels (from 0.1% to 2.0% saturation), with humidity ranging from 50% RH to 90% RH, and ambient temperature spanning 0 °C-40 °C. Technical developments that have enabled the illustrated performances, as well as future directions for conductometric microsensor research aimed at meeting the various stringent demands faced in the hazardous chemical detection application sector, are described.
AB - Several recent demonstrations of the abilities of micro-electromechanical systems (MEMS)-based microsensor technology to detect hazardous compounds and their simulants in a variety of background conditions are presented. In each case, two pairs of conductometric metal oxide sensors (TiO2 and SnO2) produced via chemical vapor deposition are operated using temperature-programmed sensing (TPS). NIST microdevices can utilize this operating mode to sample a wide operating temperature range (50 °C-480 °C) in a very short time (<15 s). The voluminous databases generated by this method can be analyzed using signal processing techniques, such as artificial neural networks (ANNs), to provide actionable outputs. Several examples are presented: cyclohexyl methyl methylphosphonate (CMMP), a simulant for cyclosarin (GF), is detected at concentrations ranging from 700 pmol/mol to 90 nmol/mol in air backgrounds ranging from 0% relative humidity (RH) to 70% RH. The chemical warfare agents (CWAs) tabun (GA), sarin (GB), and sulfur mustard (HD) are detected at 25 nmol/mol in dry air, humidified air (40% RH), and diesel fume-laden air (3.5% saturation). Finally, a selection of five toxic industrial chemicals (TICs) and one chemical warfare simulant (CWS) are measured at immediate danger to life and health (IDLH) and permissible exposure limit (PEL) levels in an array of backgrounds, including seven different interferences, each at three concentration levels (from 0.1% to 2.0% saturation), with humidity ranging from 50% RH to 90% RH, and ambient temperature spanning 0 °C-40 °C. Technical developments that have enabled the illustrated performances, as well as future directions for conductometric microsensor research aimed at meeting the various stringent demands faced in the hazardous chemical detection application sector, are described.
KW - Chemical gas microsensor
KW - Chemical warfare agent
KW - Conductance
KW - Interference
KW - Metal oxide
KW - Toxic industrial chemical
UR - http://www.scopus.com/inward/record.url?scp=33846277600&partnerID=8YFLogxK
U2 - 10.1016/j.snb.2006.09.050
DO - 10.1016/j.snb.2006.09.050
M3 - Article
AN - SCOPUS:33846277600
SN - 0925-4005
VL - 121
SP - 282
EP - 294
JO - Sensors and Actuators, B: Chemical
JF - Sensors and Actuators, B: Chemical
IS - 1
ER -