Rapid on-site detection of hazardous constituents in water supplies entails use of complex equipment with high power requirements. A simpler solution engineered by researchers from National Tsing Hua University in Taiwan and Chung-Ang University in South Korea relies on a robotic hand equipped with a triboelectric nanosensor to quickly gauge water quality.

The self-powered nanosensor was demonstrated to detect small amounts of mercury ions simply by immersion of a robotic finger into a water sample. The triboelectric device uses an array of mercury-sensitive tellurium nanowires, which build up an electrical charge as they come in and out of contact with mercury ions. The electricity generated powers the sensor, and data reflecting any change in voltage associated with the presence of mercury is wirelessly transmitted to a smartphone in real-time.

Attached to the finger pad of a robotic hand, the triboelectric nanosensor checks a liquid sample for mercury contamination. Source: American Chemical Society

Mounted on the finger pad of a robotic hand that repeatedly tapped on the surface of tap and lake water samples, the nanosensor system described in ACS Nano quickly and accurately fingered the mercury concentrations present. The sensor also detected levels of the hazardous element in samples of mercury-tainted apple, shrimp and spinach.