The Analysis for PFAS: An Evaluation of Current Methods, Proposed Methodologies and the Application of New Technologies

Polyfluoroalkyl Substances (PFAS) in the Environment (Session 2)
Oral Presentation

Prepared by C. Neslund
Eurofins Lancaster Laboratories Environment Testing, 2425 New Holland Pike, Lancaster, PA, 17601, United States


Contact Information: [email protected]; 717-556-7231

ABSTRACT

The chemistry and analysis of PFAS is unique and challenging, and there is currently no consensus “best” method for all environmental matrices. The USEPA published Method 537 in 2009 with an update in 2018. This method is applied to 18 PFAS compounds in drinking water matrices only. As of November 2019, EPA published an additional drinking water method, 533. This method was developed to target short chain PFAS compounds and utilizes different analytical techniques than method 537.1. Several other methods have been published for PFAS in non-potable and solid matrices including ISO Method 25101, ASTM D7979 and D7968. In late summer of 2021, EPA published Draft Method 1633 and is in the process of validating a number of matrices using a multi-lab validation study. The Department of Defense (DOD) has compiled quality assurance criteria for PFAS testing under Table B-15 of the Quality Systems Manual (QSM), criteria which has been adopted by a number of States. Additionally, DOD has recently added a Table B-24 of the QSM to define PFAS testing using Draft Method 1633.

In order to meet client needs, environmental laboratories have adopted Method 537 and developed significant modifications to address non-potable water and solid matrices. The opportunity existed for labs to make unique and unqualified modifications and these modifications yielded opportunity for data variability over time and between labs. The adoption of the Table B-15 criteria helped to normalize this. With the advent of Draft Method 1633 and eventual validation, a further “normalization” of laboratory practices could be anticipated.
Additionally, several other techniques are in either use or being developed for use as a compliment to the targeted compound mix of methods referenced above. These include TOP Assay, Total Organic Fluorine (TOF) and Non-Target Analysis (NTA) using qTOF (quadrapole time of flight) mass spectrometry. This variety of options leaves many practitioners with the very challenging job of deciding, what is best for assessing the extent (or presence) of PFAS contamination. This presentation will attempt to provide some level of clarity on how to resolve that decision-making.

This presentation will look at the current state of analytical methods for the analysis of PFAS and will provide the following:
• Methods Comparison – A look at published drinking water methods
• Methods for non-potable water, solid and air matrices – the user defined methods available today and Draft Method 1633
• Key analytical techniques
• Matrix specific considerations
• A review of state specific method requirements
• An introduction/review of new techniques for PFAS determination to compliment targeted compound approaches