Pitt researchers use fluorescence to develop method for detecting mercu...( PITTSBURGHResearchers at the Univers...)

PITTSBURGHResearchers at the University of Pittsburgh have developed a simple and quick method for detecting mercury in fish and dental samples, two substances at the center of public concern about mercury contamination. The technique involves a fluorescent substance that glows bright green when it comes into contact with oxidized mercury, the researchers report in the current online edition of the Journal of the American Chemical Society. The intensity of the glow indicates the amount of mercury present.

Developed in the laboratory of Kazunori Koide (Ko-ee-deh), a chemistry professor in Pitt's School of Arts and Sciences, the new method can be used onsite and can detect mercury in 30 to 60 minutes for dental fillings (or amalgams) or 10 to 30 minutes for fish, Koide explained. "Our method could be used in the fish market or the dentist office," he said. "We have developed a reliable indicator for mercury that a person could easily and safely use at home."

The fluorescence results from the reaction of mercury ions with hydrocarbons called alkynesthe alkyne is converted into a ketone and creates a fluorescent molecule. Koide's method differs from similar mercury indicators in that it withstands the oxidation process mercury samples must undergo prior to testing, Koide said. The mercury species found in most fish and dental amalgamssuch as the toxic methyl mercurymust be converted into a safer variety of mercury with an oxidizing agent. Other fluorescent detectors are often not compatible with samples that have been oxidized.

In testing fish, Koide and his team oxidized a piece of salmon (about the size of a fingertip) in water mixed with a chlorine solution similar to household bleach. The conversion process is safe and relatively simple, Koide said. Afterward, the team added the alkyne solution and the mixture glowed bright green.

The Pitt researchers also tested for mercury leaching from dental amalgam, a common toot
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