In a latest research color changing sensor detects lead in water within seconds.

A team of Indian researchers has designed a new renewable, naked-eye sensor that can detect ultra-trace levels of lead (pb²⁺) in environmental and commercial samples. the innovation lies in using specially engineered porous hybrid materials that allow direct visual detection through a quick color change.

the researchers synthesized a unique chromoionophoric molecule called (e)-1-(benzo[d]thiazol-2-yldiazenyl)naphthalen-2-ol (btdn) and immobilized it on two porous host materials: a metal–organic framework (uio-66) and a hybrid polymer monolith known as poly(tmspma-co-tmpta). these frameworks serve as stable, high-surface scaffolds that improve the sensor’s sensitivity and response speed.

when exposed to lead ions, the sensor changes color from apricot to a deep claret red, allowing instant visual detection without any equipment. the system responds within 60 seconds and can detect lead concentrations as low as 0.14 µg/l — far below many regulatory limits for drinking water.

beyond sensitivity, the sensors are renewable, portable, and environment-friendly. their solid-state design ensures stability, long shelf life, and scalability for large-scale water monitoring. researchers say the device could be used for real-time assessment of water quality and on-site testing of industrial wastewater.

lead contamination remains one of the most persistent environmental threats worldwide. innovations like this color-changing sensor mark a step toward faster, cheaper, and more accessible monitoring technologies.

Source: https://doi.org/10.1007/s42114-025-01440-9