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Ion test has BYU glowing

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PROVO — Imagine this Hollywood moment: Looks of concern cross handsome faces as researchers huddle near a row of test tubes, watching molecules glow in water samples taken from New York City. The fluorescent spots, as the plot reveals, indicate huge amounts of toxic chemicals in the water.

Only in Tinseltown? Think again. Such a scenario could be coming to a laboratory near you, thanks to a team of Brigham Young University researchers.

The BYU discovery, featured on the cover of last week's American Chemical Society's "Journal of Organic Chemistry," is considered a step toward easier and quicker ways to detect specific pollutants in water.

"Methods of tracking metal in water currently exist, but they're labor intensive and can be very slow," said Paul B. Savage, a BYU chemistry professor and co-author of the $500,000 study funded by the Office of Naval Research.

Researchers at BYU have created doughnut-shaped molecules that glow a fluorescent color when they contact certain metal pollutants in water that are believed to be caused by mining, smelting and fossil-fuel combustion.

Savage said the intensity of the glow is directly proportionate to the amount of metal detected in the water.

"It can get bright," he said with a small laugh.

But you can't see the abundance of metals in the water by looking into a crystal goblet. The study published in the journal, which is edited by Peter J. Stang, a noted University of Utah chemist, details how the BYU team worked in the laboratory to design and create molecules for the project.

The synthetic molecules were then tested to see how they responded to zinc when examined under ultraviolet light. And in two other studies, the specially designed molecules were exposed to such metals as cadmium and mercury to test reactions.

To detect the metals in the water, the team first made compounds that seek out and bind to metal ions, which are atoms with extra electrons. Then the team created small molecules that attach to the metal-binding compounds.

The molecules are built to detect specific metals, he said. The presence of bound metal ions is shown by fluorescent "reporters." When ultraviolet light is flashed, the reporters glow brightly. But if no metal ion is found, it remains dark.

The color depends on the type, Savage said. Cadmium beams a beautiful, bright blue. "If it binds on zinc, it glows orange," Savage said. "If it glows yellow, it has bound twice."

The benefits of producing technology to more effectively identify amounts of "toxic and environmental threats" in water sources are obvious, he said.

For example, damage to the nervous system and corrosion of the digestive tract can be caused by exposure to high levels of mercury. A limit of two parts of mercury per billion has been established by the U.S. Environmental Protection Agency.

Zinc, an essential dietary element, can be dangerous in large doses. Some signs of too much zinc intake include low blood pressure and painful urination.

Cadmium is found often at industrial sites where ore is being processed or smelted and has been linked to renal dysfunction and increased rates of some cancers. According to the EPA, from 1987 to 1993, cadmium releases were primarily from zinc, lead and copper smelting and refining industries, with the largest releases occurring in Arizona and Utah.

But researchers are scratching their heads about how to detect lead in water with the metal-ion experiment. Properties in lead typically kill the fluorescence. They are now working on molecules that will effectively work to detect lead and arsenic.

The BYU team hopes the next generation of the research will lead to a small optical sensory device to test metal-ion concentrations. As envisioned, it would be equipped with an electronic device that would record the samples and could be later downloaded to a computer.

"The idea is for continual monitoring," said Savage.

That will make it easier for water-quality bosses to respond to problems more quickly, he said. "In any normal water source, there are going to be a lot of metal ions in there," Savage said. "This allows us to ignore the ions that are not of interest and identify the ones that are of interest."

E-MAIL: jeffh@desnews.com