Date: Dec 01, 2009 Source: MDA (
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by Joan M. Zimmermann/jzimmermann@nttc.edu
Eight sensors on a platform the size of an eraser can tell you where a variety of gas leaks are hidden, and just how much of each kind is leaking.The minimalist sensor system, developed by Seacoast Science, Inc. (Carlsbad, CA), is based partly on funding from an MDA Phase I SBIR contract in 2005.
The agency's goal was to create a flexible detector for the dangerous propellants used in missile defense applications. The system developed for MDA included a chemical sensor array optimized for oxidizers and hypergolic fuels—which ignite when their components come in contact, rather than relying on outside ignition sources. The Seacoast technology also could include a radio for wireless communication in a small, rugged, lightweight, low-power system designed for long-term battery operation.
Seacoast Science's miniature gas chromatograph should help universities conduct safe and inexpensive science lab courses.
Seacoast's current product relies on a simple polymer "sponge" sandwiched between two tiny plates of silicon. The configuration quickly and inexpensively allows the company's device to quantifiably recognize dangerous toxins—organophosphate pesticides, for example. Seacoast also has developed a pre-concentrator that can either concentrate low amounts of volatile gases or that can turn solid matter, such as explosives, into a volatile sample and then deliver the substance to the sensor for analysis.
The success of the system depends on Seacoast's microelectromechanical systems (MEMS) chemicapacitor technology, resulting in an assortment of surface-micro-machined capacitors. These capacitors, which affect the characteristics of an electrical signal when their target chemical is detected, are coated with chemoselective polymers. Each sensor is impregnated with a polymer designed to respond to a specific chemical, such as the various types of hydrazine fuels.
Seacoast's Chris Neidre says that the SBIR contract allowed the company to expand its polymer selection, leading to new polymers for applications such as the BSP3 polymer, which was developed at Pacific Northwest National Laboratory. BSP3 detects organophosphates in a dose-response manner—i.e., the more organophosphate in an area, the greater the response of the capacitor. BSP3 would be ideal as the polymer used for a small sensor worn on the clothing of soldiers at risk for attack by nerve gas, or for first responders to the scene of a chemical accident. The sensors in general can be used to detect narcotics, volatile organic compounds, toxic industrial chemicals, chemical warfare agents, and toxic mold. Seacoast's technology is being examined with an eye to putting chemical sensors in cell phones as an early warning system for emergency personnel. Another example of an application would be to place the sensors along the levees of the Mississippi River to monitor chemicals from an industrial spill or shipping accident, for real-time situational awareness.
Seacoast has focused its chemical-sensing expertise on two areas of commercial development. The first is in the provision of simple and low-cost gas chromatography kits for high schools and universities. Many of these institutions are prohibited from using compressed gases in laboratory courses, to which Seacoast responded by creating the Vernier Mini Gas Chromatograph (GC), which operates on ambient air instead of injected inert gases. By taking the gases out of the equation, Seacoast addresses the safety issue as well as the cost. Instead of investing in a $25,000 gas chromatograph, a school can purchase the Mini GC for $1,749, including related equipment and reagents for experiments. The experiments supported by Vernier Software and Technology are as diverse as ketone separations, esterifications, and identifying components in whiskey. The kit's price represents a 14-fold decrease over a full-sized GC device, which does not include the reagents and additional tools needed to carry out a typical lab. Seacoast's new line of academic GCs are available in the Vernier catalog, which supplies high schools and universities with lab equipment. (http://www.vernier.com/probes/gc-mini.html)
Seacoast is developing a field-portable gas chromatograph, called the SeaPort Mini GC, which is envisioned for pesticide monitoring in agriculture, process monitoring in all types of manufacturing that use toxic volatiles, illicit drug lab detection, and water quality investigations.
Seacoast is licensing the BSP3 polymer from Battelle and manufacturing the sensors for wider distribution. In addition, the company has compiled a library of "secret sauces" for impregnating its polymer chemicapacitor, for detecting the presence of a large variety of chemicals.
