Development of a Robust Quantitative Analysis Procedure for PIGE Spectra

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that have become a major environmental concern. They can be found in a broad range of products including food packaging, stain- and water-repellent fabrics, nonstick products, makeup, fire-fighting foams, and electronics. These chemicals do not break down easily in the environment, can bioaccumulate, and some can lead to adverse health effects. We are working on a system to screen for these chemicals using proton-induced gamma-ray emission (PIGE) in the Union College Ion-Beam Analysis Laboratory. Samples are bombarded in air with 1.8-MeV protons from the external beam facility on our 1.1-MV Pelletron tandem accelerator. The emitted gamma-rays are detected with a high-purity Ge detector. Currently, samples are screened for the presence of PFAS chemicals within 3-5 minutes by looking for the characteristic fluorine gamma-rays at energies of 110 and 197 keV. Furthermore, we have aimed to implement a fully robust quantitative procedure to measure the concentration of fluorine in soil, water, and paper samples. The goal is to develop methods to quickly format and fit data to determine gamma-ray yields corresponding to our key peaks. Then by utilizing a standard-based method, we will be able to determine concentration ranges of fluorine in our samples. As we begin to develop a greater quantity of precise standards, we will be able to quantify our results even further. In addition to this standard-based approach, we hope to employ the use of known PIGE cross-sectional data. While this cross-sectional data is still in the early stages of research, it will provide a secondary and hopefully more precise method to calculating exact concentrations values. It will be our goal to actively employ this procedure in the near future to screen a wide variety of materials for hazardous amounts of PFAS.