Automated Extraction of PFAS Comparison to Manual Method for Field-Contaminated Samples

Abstract

Per- and polyfluoroalkyl substances (PFAS) are known to be a problem; they permeate every part of our lives. The question becomes: what is the best solution for accurate, reproducible, manageable testing? The solution is even more challenging when considering solid sample types that require a solvent extraction step, adding another step and potential complication to the overall analysis. EPA Method 1633A¹ has taken a major leap forward in creating a protocol and standard by which PFAS analysis can be performed that includes solid samples. However, the solvent extraction section of this method is a manual process that is long and labor-intensive, delivering inconsistent results and susceptible to human error.

These limitations have been addressed by shifting to the EDGE PFAS™ system, an automated solvent extraction system that has been shown to have little to no contamination issues and reduces the possibility of human error while also shortening the sample preparation time. To assess performance, a soil certified reference material (CRM) and field-contaminated soils were processed by both manual and automated solvent extraction. All sample preparation, extraction, cleanup, and LC-MS/MS analyses were outsourced to a certified laboratory. The CRM results demonstrated all analyte recoveries within acceptance limits for both the manual and automated workflows. Additionally, PFAS results from two air-dried AFFF field-contaminated soil samples showed equivalence between the automated extraction approach and the manual procedure outlined in EPA Method 1633A. Collectively, these findings support the use of the EDGE PFAS system as a reliable alternative solvent extraction technique for soil samples analyzed under EPA Method 1633A.