Ultrasonic levitation helps detect water contamination

(Cedit: Jairo Peralta and Victor Contreras, Instituto de Ciencias Físicas UNAM)

Laser induced breakdown spectroscopy (LIBS) is commonly employed to identify what chemicals are present in a particular sample of a substance. While this is a straightforward process with solids, it is more difficult with liquids, as the plasma created by the laser pulse lasts such a short time, making the chemical fingerprint hard to detect. Typically, samples of water have to be sent to laboratories where high-powered, non-portable lasers perform the task.

Using sound waves, the researchers suspended a single droplet of water that allowed them to detect very low concentrations of heavy metals using LIBS. In their paper, published in the journal Optics Letters, they detected 0.7mg/L of cadmium and 0.2mg/L of barium. It’s hoped that the work will form the basis of a portable or handheld device that can perform vital water analysis on-site.