Nano-velcro measures toxic metals in fluids
11 Sep 2012
Researchers have developed a method of measuring water-born toxic chemicals using a strip of glass covered in nanoparticles.
Scientists at the Swiss Federal Institute of Technology (EPFL), Northwestern University, and the University of Michigan found that their new method can measure methyl mercury at unprecedentedly small concentrations.
“Current monitoring techniques are too expensive and complex,” said Francesco Stellacci, co-author and Constellium Chair holder at EPFL.
“With a conventional method, you have to send samples to the laboratory, and the analysis equipment costs several million dollars.”
Using the device invented by the Swiss-American team, measuring the mercury levels in water or dissolved fish meat involves 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.
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 on-site and within minutes.
Funding for this research came from ENI, via the ENI-MIT Alliance; the US Defense Threat Reduction Agency via a grant to MIT and the University of Michigan; and the US Department of Energy.
