Soviet ‘Spy Dust’ Called a Simple Compound

WASHINGTON — The Soviet “spy dust” used to track American diplomats may sound like material from a James Bond movie, but the compound identified as nitrophenylpentadiene, or NPPD, actually is so simple that “you could have undergraduates prepare it in a high school lab,” one national expert on such substances said Wednesday.

Nicholas J. Turro, an organic photochemist at Columbia University in New York City, said the chemical is a straightforward variant of retenal, an organic chemical involved in human vision, with a chain of five carbon atoms attached to one end. The substance is very likely fluorescent, Turro said, and it almost certainly is a solid at room temperature.

The carbon atoms also probably make the chemical stick to fat molecules in the skin, said Turro and Robert Michaels, a scientist with the Natural Resources Defense Council in New York.

“The same proteins that latch on to retenal to make it important in vision could react with this . . . to make it stick to you,” Turro said. “You could put it on the bottom of someone’s shoe, and as they walk around they’d leave a little bit of it. It’s like Hansel and Gretel, but instead of throwing around bread crumbs, you throw around this chemical.”