This new and cost-effective technology can easily detect dangerous chemicals called PFOA and PFOS in water, and is also suitable for detecting them in contaminated areas.
Water can contain many types of chemicals that can harm the health of any living organism. Among which are per- and polyfluoroalkyl substances (PFAS) , a class of highly fluorinated substances that pose a threat to people and the environment.
Particularly dangerous chemicals in this class, such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), can cause organ damage and cancer , as well as disrupting endocrine system function.
In the journal Angewandte Chemie , researchers have now developed an affordable, easy-to-use sensor for testing for PFAS in water samples.
The term per- and polyfluoroalkyl substances (PFAS) refers to a group of organic compounds in which most or all of the hydrogen atoms attached to carbon atoms have been replaced with fluorine atoms. They are used to provide oil resistance to a variety of products, such as nonstick pans, clothing and packaging.
They can also be found in fire extinguishing foam, paint, and car polish. These compounds are extremely useful but also extremely dangerous. When they find their way into the environment, they do not break down and thus reach plants, animals and people.
The EU limits for drinking water are 100 ng per liter for specific PFAS substances and 500 ng per liter for the total of all PFAS. In Germany, water supply providers will have to start testing drinking water for PFAS in 2026, the research said.
The US Environmental Protection Agency has set strict limits for these, for the most widespread PFAS (PFOS and PFOA), the upper limit for each substance is set at four nmol per liter.
Common methods used for such quantitative detection include chromatography and mass spectrometry, which are time-consuming and expensive. It requires complex equipment and experienced personnel.
Timothy M. Swagger and Alberto Conselon at the Massachusetts Institute of Technology (MIT) in Cambridge, US, have now introduced technology to create a portable, affordable test that can easily and selectively detect PFAS in water samples. Uses measurement.
This test is based on a polymer with a fluorinated sidechain in the form of a thin film or nanoparticle to which fluorinated dye molecules (squarene derivatives) are attached. The special polymer backbone (poly-phenylene ethynylene) absorbs violet light and transfers the light energy to the dye by electron exchange (Dexter mechanism).
Then after colliding with the dye it turns red. If PFAS are present in the sample, they penetrate the polymer and displace the dye molecules by a fraction of a nanometer. This is sufficient to prevent electron exchange and thus energy transfer. When the red fluorescence of the dye is “off”, the blue fluorescence of the polymer is “on”. Each degree of change in fluorescence is proportional to the amount of PFAS.
This new technology, which has detection limits in the range of micrograms per liter for PFOA and PFOS, is suitable for on-site detection in highly contaminated areas . Detection of very small amounts of these hazardous chemicals in drinking water can be achieved with accuracy after pre-quantification of samples by solid-phase.
