Continuous water quality monitoring between water supply intakes/treatment plants and the consumer’s faucet is essential to avoid public health crises such as that affecting Flint, Mich.

A graphene-based sensing platform for this application has been developed by University of Wisconsin-Milwaukee researchers, who presented their work during the AVS 64th International Symposium & Exhibition, The handheld device includes a sensor enclosed in a test cell and attached to a digital meter. Source: University of Wisconsin-Milwaukeeheld Oct. 29-Nov. 3, 2017, in Tampa, Fla.

The sensor offers real-time, low-cost detection of various water contaminants, including heavy metals, bacteria, nitrates and phosphates. Deployment of such sensors in water distribution systems could provide early warning of contaminants in water supplies.

“Intrinsic graphene is a zero-gap semiconductor that has remarkably high electron mobility (100 times greater than that of silicon), which makes it attractive for sensitive, high-speed chemical and biological sensors due to its high sensitivity to electronic perturbations,” said Junhong Chen, distinguished professor of mechanical engineering, materials science and engineering.

Semiconducting graphene-based nanosheets are placed between an electrode gap. The electrical conductivity of the graphene material changes with the binding of substances to its surface and their chemical constituents are identified and measured.

A prototype of a hand-held device for detection of lead ions in drinking water has been developed with National Science Foundation funding. The sensor is based on a field-effect transistor device with reduced graphene oxide as its sensing channel, and the technology can be extended to detect analytes in food and beverages, or for biomedical applications.