Key points:
- A new luminescent sensor can detect PFOS in industrial wastewater.
- The sensor works by using a small gold chip grafted with iridium metal complexes.
- With a working prototype, the team is now committed to improving its sensitivity so it can be used to test drinking water.
Researchers have created a new way to detect PFAS pollution in water—via a luminescent sensor.
Current methods for the measurement of these contaminants, also called “forever chemicals,” are difficult, time-consuming and expensive.
“There is a clear and pressing need for a simple, rapid, cost-effective method for measuring PFAS in water samples onsite to aid containment and remediation, especially at (ultra)trace concentrations. But until now, it had proved incredibly difficult to do that,” said Stuart Harrad, professor of environmental chemistry at the University of Birmingham and co-led on the design of the new sensor.
Harrad and team have created a prototype model that detects the perfluorooctanoic acid (PFOA) through an approach that uses luminescent metal complexes attached to a sensor surface. The sensor works by using a small gold chip grafted with iridium metal complexes. UV light is then used to excite the iridium, which gives off red light. When the gold chip is immersed in a sample polluted with PFOA, a change of the signal in the luminescence lifetime of the metal is observed to allow the presence of the chemical at different concentrations to be detected.
According to the study, published in Analytical Chemistry, the sensor has been able to detect 220 micrograms of PFAS per liter of water thus far—which works for industrial wastewater but not for drinking water.
“For drinking water, we would need the approach to be much more sensitive and be able to detect nanogram levels of PFAS,” said co-designer Zoe Pikramenou, professor of inorganic chemistry and photophysics.
Now that they have a working protype sensor chip, the team says they intend to refine it and integrate it to make it portable and more sensitive.
“PFAS are used in industrial settings due to their useful properties, for example in stain-proofing fabrics. But if not disposed of safely, these chemicals pose a real danger to aquatic life, our health and the broader environment. This prototype is a big step forward in bringing an effective, quick, and accurate way to detect this pollution helping to protect our natural world, and potentially keep our drinking water clean,” said Pikramenou.