A strip of glass covered in hairy nanoparticles can cheaply and conveniently measure mercury, which attacks the nervous system, and other toxic metals in fluids.
Researchers have found that their new method can measure methyl mercury, the most common form of mercury pollution, at unprecedentedly small concentrations. The system, which could test for metal toxins in drinking water and fish, is reported in the current edition of Nature Materials.
Methyl mercury dumped in lakes and rivers accumulates in fish, reaching its highest levels in large, predatory fish such as tuna and swordfish. Young children and pregnant women are advised to avoid eating these fish because mercury can affect the developing brain and nervous system. While metals in drinking water are measured periodically, these measurements say little about migratory fish, including tuna, which may pass through more polluted areas.
Using the device invented by the Swiss-American team, measuring the mercury levels in water or dissolved fish meat is as simple as dipping a strip of coated glass into the fluid. Metals and metallic molecules, such as methyl mercury, typically become positively charged ions in water. When these ions drift between the hairy nanoparticles, the hairs close up, trapping the pollutant. Passing a current over the strip of glass reveals how many ions are caught in the "nano-velcro." Each ion allows the strip to conduct more electricity.
Researchers performed computer simulations that investigated how the nano-velcro traps pollutants. They showed that the hairy nanoparticles are choosey about which ions they capture, confirming that the strips can give reliable measures of specific toxins.
The scientists targeted particular pollutants by varying the length of the nano-hairs. This approach is especially successful for methyl mercury, and the device can measure it with record-breaking accuracy, detecting concentrations as low as 600 methyl mercury ions per cubic centimeter of water. Fortunately, that level of precision won't break the bank. The researchers estimate that the coated glass strips could cost less than 10 dollars each, while the measurement device will cost only a few hundred dollars. It could gauge the concentration of metals onsite and within minutes.
This story is reprinted from material from University of Michigan, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.