Sensors based on fluorescent molecules could detect metal pollutants
A team of Brigham Young University (BYU; Provo, UT) researchers has created molecules that glow in the presence of certain metal pollutants, paving the way for an early warning system that can alert regulators to the contamination of drinking water and waste streams.
Because excesses of certain metals in a person's diet pose a health threat, BYU researchers devised the molecules as an improved method of detecting and monitoring increased metal levels in the environment caused by mining, smelting, fossil fuel combustion and industrial use. Their work was highlighted in the July 13th issue of the American Chemical Society's Journal of Organic Chemistry.
“Methods of tracking metal in water currently exist, but they're labor intensive and can be very slow,” says researcher Paul Savage, associate professor of chemistry. “This research will let us create a sensor that continually measures metal in a sample of water as it flows by, making it easier to respond to any problems more quickly.”
The article describes step-by-step how the team designed and created the molecules in the laboratory and reports how the molecules respond to zinc in the presence of ultraviolet light. The team has also recently published two papers about synthetic molecules created to indicate the presence of mercury and cadmium.
To detect metals in water like zinc, BYU researchers first created compounds that seek out and bind to metal ions --those atoms with extra electrons. Next, they created small molecules that attach to the metal-binding compounds. The small molecules reveal the presence of bound metal ions by acting as fluorescent reporters “ when ultraviolet light is shined on them, the reporters glow brightly. If no metal ion is bound, the compounds remain dark. The color of the glow depends on the type and concentration of the metal ions present.
Plans are underway to develop a device that will allow industrial plants and water treatment facilities to track the concentration of metal ions in water and waste streams over time, said Savage.
The lead researcher was emeritus professor of chemistry Jerald S. Bradshaw. Assisting Bradshaw and Savage were BYU researchers Reed M. Izatt, R. Todd Bronson, Saowarux Fuangswasdi, Sang Chul Lee and collaborator Krzysztof E. Krakowiak.