Polyfluoroalkyl substances (PFASs) do not break down easily in the environment. Most Americans have detectable levels of PFAS in their blood, causing health problems. This links kidney and testicular cancer, hyperlipidemia, thyroid disease, and others. PFASs can enter human bodies through drinking water, food chains, and aquatic ecosystem. The EPA has a national advisory limit of 70 parts per trillion (ng/L) for drinking water quality, and set a standard method based on LC-MS. But it is still unknown what amount of PFAS will harm personal health. Some states have enforceable limits lower than the EPA advisory limit. Massachusetts has a limit at 20 ng/L. Previous toxicology research suggested the PFAS limits in drinking water should be lower than 1 ng/L, which current EPA methods cannot detect. The limitations of LC-MS inhibit the advancement of already-limited PFAS research and the creation of better public health regulations. This research studied the surface-enhanced Raman spectroscopy (SERS) for the detection of trace PFASs. SERS is an ultra-sensitive optical sensing technique that has the potential for trace substance detection. Solutions of PFOA and PFOS, two of the most widely manufactured PFASs, were used to demonstrate SERS detection of PFASs and to create calibration curves to enable quantitative analysis. In this study, silver nanoparticles (AgNPs) were mixed with PFOA and PFOS solutions and drop-cast on alumni foil for the test. A feature peak of the difluoromethylene group (CF<sub>2</sub>), which makes up the backbone of PFASs, was identified for the analysis. Logarithmic serial dilutions of PFOA and PFOS, ranging from 1 g/L to 20 fg/L, were created. The serial dilution spectra were plotted to create calibration curves. Field samples representing different types of water sources (pond, river, reservoir, and public/private tap) were collected in four seasons to monitor seasonal variation and were analyzed using the SERS. In this preliminary study, we have demonstrated that SERS is a highly sensitive and fast method for PFAS analysis in water sources; a trace PFAS concentrations as low as 20 fg/L were detected.

Study of trace PFAS detection in water sources by SERS with silver nanoparticles

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.