This proof-of-concept project was designed to develop and validate a low cost, rapid screening-level analytical technique for measuring individual per-and polyfluoroalkyl substances (PFAS) at low part per trillion concentrations in environmental samples. At present, this type of analytical screening tool is not commercially available to investigation and remediation teams. This is mainly due to the extraordinarily low detection limit requirements for PFAS and the complex nature of PFAS analytical chemistry.

The research team used the Echo^® MS+ system which is comprised of a novel sample introduction technique that delivers the sample, via acoustic energy, directly into the mass spectrometer detection system. The technique does not use any solid phase extraction or liquid chromatography and is therefore faster and potentially less expensive than the standard PFAS analytical techniques. Method development and optimization of the Echo^® MS+ method was followed by a comparison study to evaluate the performance of this screening-level method against a definitive analytical procedure (USEPA Draft Method 1633). The comparison study was focused on determining the reliability of the Echo^® MS+ for making interim, field-based decisions and a more traditional evaluation using correlation and relative percent difference statistics. Additionally, an analytical method performance evaluation was conducted to determine the throughput and related costs for conducting the Echo^® MS+ analyses.

Based on the information generated from this work, the Echo^® MS+ system in its current state lacks stability and is not able to routinely generate PFAS data with sufficient quality for use as a screening-level method. However, a modified protocol was implemented to conduct replicate analyses to try and mitigate the effects of the high degree of variability within the technique. The results from this modified protocol showed significant improvements to the reliability and accuracy of the technique. The other key finding was related to the data handling and reporting capabilities of the Echo^® MS+ system, which are not fully developed and require significant effort to report routine quality assurance and quality control data and sample results. Overall, the technology showed promising results but would need significant improvements in order to generate reliable, accurate, and affordable PFAS data.

The results of this work provide a solid understanding of the limitations and capabilities of the Echo^® MS+ analytical technique, and the basis for future work to improve the technology to a point where it can be cost-effectively used as a screening-level technique. The investigators believe a low cost, rapid technique that is capable of targeted PFAS analyses at the part per trillion level will bring significant improvements to the efficiency of PFAS site investigation and remediation work. (Project Completion - 2026)