Let it glow

Scientists develop new approach to detect ‘forever chemicals’ in water through a unique technological finding.

Scientists have developed a new approach to detect ‘forever chemicals’ in water.

Scientists in Chemistry and Environmental Science at the University of Birmingham have developed a new approach for detecting pollution from ‘forever chemicals’ in water through luminescence. This was conducted in collaboration with scientists from the Bundesanstalt für Materialforschung und -prüfung (BAM), Germany’s Federal Institute for Materials Research and Testing.

PFAS or ‘forever chemicals’ are manufactured fluorine chemicals used widely in different industries. It covers many sectors, from food packaging to semiconductor production and car tires. They are non-degradable and accumulate in the environment. Concerns regarding the toxic pollution they cause, particularly in water, have risen recently.

Stuart Harrad, Professor of Environmental Chemistry at the University of Birmingham, co-led the design of a new sensor. He worked with colleague Professor Zoe Pikramenou, Professor of Inorganic Chemistry and Photophysics.

“Identifying ‘forever chemicals’ in any location is crucial for our health and the health of our planet,” said Harrad. “Current methods for measurement of these contaminants 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. This is especially the case at (ultra)trace concentrations. But until now, it had proved incredibly difficult to do that.”

The researchers have published their findings in Analytical Chemistry. They have created a prototype model that detects the ‘forever chemical’ perfluorooctanoic acid (PFOA). The approach uses luminescent metal complexes attached to a sensor surface. If the device is dipped in contaminated water, it detects PFOA by changes in the luminescence signal given off by the metals.

What were the findings around forever chemicals?

“The sensor uses a small gold chip grafted with iridium metal complexes,” said Pikramenou. “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 the ‘forever chemical’, a change of the signal in the luminescence lifetime of the metal is observed to allow the presence of the ‘forever chemical’ at different concentrations to be detected. So far, the sensor has detected 220 micrograms of PFAS per litre of water, which works for industrial wastewater. Still, for drinking water, we would need the approach to be much more sensitive and detect nanogram levels of PFAS.”

The team has collaborated with surface and sensor scientists BAM in Berlin for assay development and dedicated analytics at the nanoscale. Dan Hodoroaba, head of BAM’s Surface and Thin Film Analysis Division, emphasised the importance of chip characterisation.

“Advanced imaging surface analyses are essential for developing dedicated chemical nanostructures on customised sensor chips to ensure optimal performance,” said Hodoroaba.

Knut Rurack, who leads the Chemical and Optical Sensing Division at BAM.

“Now that we have a prototype sensor chip, we intend to refine and integrate it to make it portable and more sensitive,” said Rurack. “It can be used on the site of spills and to determine the presence of these chemicals in drinking water.”

“PFAS are used in industrial settings due to their useful properties, for example, in stain-proofing fabrics,” added Pikramenou. “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 in bringing an effective, quick, and accurate way to detect this pollution. It will help to protect our natural world and potentially keep our drinking water clean.”

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