Photonics.com CUERNAVACA, Mexico, May 4, 2018 — A new approach to detecting metal contaminants in water involves the use of laser-induced breakdown spectroscopy (LIBS) to analyze the presence of heavy metals, such as mercury, in water drops that are levitated in midair using ultrasonic waves.
Levitating the water droplets allows the water to evaporate in a controlled position, which increases the mass concentration of contaminants in the sample and makes it easier to perform LIBS analysis.
Using this method, researchers from Instituto de Ciencias Físicas UNAM detected even very low concentrations of heavy metals.
Researchers used sound waves to levitate droplets of water.
This approach allows the water to evaporate, which concentrates the sample for spectroscopic detection of harmful heavy metal contaminants, such as lead and mercury, in water.
To circumvent the need for bulky, nonportable lasers, liquid samples are typically analyzed by placing a drop on a substrate and waiting for it to dry, in order to concentrate the elements of interest in the sample.
The process, from placing the sample in the acoustic levitator to the chemical identification of the trace elements, takes only a few minutes.
A water droplet was analyzed with laser-induced breakdown spectroscopy (LIBS), which uses a high-energy laser pulse to vaporize the sample and generate a plasma.
“This technology has the potential to simultaneously detect heavy metals and other elements in water in a fast and cost-effective way,” said Contreras.
They also want to increase the sensitivity by stably levitating smaller drops, which would further concentrate the contaminants.