Z. Xia
Goeppert LLC,
United States
Keywords: PFAS detection, solid-state nanopore, sensor
Summary:
PFAS refers to a class of thousands (potentially millions by European definitions) of synthetic fluorinated organic chemicals manufactured over the past 80 years. Over the last 15 years, the EPA has developed highly precise analytical methods, including Methods 533, 537.1, and 1633, to quantify single PFAS at ppt levels. However, due to limited commercially available reference standards, most laboratories can analyze only a small subset of compounds—Method 1633, for example, targets just 40 PFAS compounds. This limitation highlights the need for broader detection tools to assess PFAS contamination comprehensively. Regulations for total PFASs will also require better methods for detection and quantification. Many state-of-the-art systems rely on mass spectrometry (e.g., LC-MS/MS), which offers high sensitivity but is expensive, time-consuming, and requires trained personnel. Several other detection techniques are emerging but are not yet able to reliably determine total PFASs in samples. There is a need for PFAS and total organofluorine sensors that offer portability, simplicity, and low-cost deployment without sacrificing accuracy. The project explores using solid-state nanopore chips for rapid, reliable, portable, and low-cost total PFAS detection. It integrates advanced nanofabrication, high-throughput data collection, and reliable data analysis to improve overall PFAS detection capabilities. The proposed nanopore sensor has been semi-validated in a previous NIEHS SBIR Phase I project (1R43ES034321) using DI water spiked with known PFAS concentrations and types. Specifically, thin (~20 nm) and small (5-10 nm) silicon nitride nanopores were fabricated and coated with fluorinated silanes that exhibit group selectivity for PFAS compounds through specific fluorine-fluorine hydrophobic interactions. Total PFASs were detected at ppt levels and even lower. This technology provides an innovative solution to monitor a wide variety of PFASs and can serve as a frontline tool for total PFAS detection. It will also make monitoring of total PFASs in home well systems affordable and provide public and private environmental protection organizations with a portable sensor for identifying PFAS contamination in the environment, thus aiding in the protection of health and waterways. Successful PFAS detection will also enable authorities (USEPA) to establish protective levels for aquatic life and humans.