Prof. Sharon Weiss has modified white gold leaf paper so that its surface provides signal amplification of 100 million times – so that a laser and detector to identify the chemical molecules of whatever it has been applied to.
“We start with a very thin, white gold film and use a simple chemical soak and one-step direct imprinting process to create what is essentially a fancy gold sponge,” said Weiss, an associate professor of electrical engineering and physics who also serves on the Edgewood Chemical Biological Center’s Research and Technology Directorate at Aberdeen, Md.
“It looks like a thin metal sheet, similar to aluminum foil, and if you shine light on it you can see different colors just like those that reflect off a CD when you shine sunlight on it,” she said.
The foil is applied to the surface being tested, then placed inside a portable measurement tool that consists of a laser and detector that analyzes it. “Encoded in the reflected light is the identity of chemical molecules in the sample,” she said.
Weiss said the system will be available commercially in about a year.
Military or security officials testing for explosives at checkpoints or airports now use large mass spectrometers or ion mobility spectrometers that require first ionizing a sample before they can identify trace amounts of explosives, according to Weiss.
She said her system is faster.
“Swab the door handle or trunk, and know instantly whether there is explosive residue,” she said.
It will also be less expensive – costing about $10 per test as opposed to the $60 it costs now.
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