An Inter-Laboratory Study on EPA Methods 537.1 and 533 for Potable and Non-Potable Water PFAS Analyses

Drinking Water
Oral Presentation

Prepared by Y. Li1, R. Hrabak2, M. Ramos3, C. Ratcliff4, C. Neslund4, J. Whitaker1
1 - Eurofins Eaton Analytical, LLC, 110 South Hill Street, South Bend, IN, 46617, United States
2 - Eurofins TestAmerica, 880 Riverside Parkway, West Sacramento, CA, 95605, United States
3 - Eurofins Eaton Analytical, LLC, 750 Royal Oaks Drive, Suite 100, Monrovia, CA, 91016, United States
4 - Eurofins Lancaster Laboratories Environmental, LLC, 2425 New Holland Pike, Lancaster, PA, 17605, United States

Contact Information: [email protected]; 574-474-5562


Human exposure to per- and polyfluoroalkyl substances (PFAS) has become a worldwide public health issue. Reports have estimated that over 3,000 PFAS exist on the global market, used in a wide variety of industrial and consumer applications. The industry has introduced shorter chain PFAS as an alternative to the legacy long-chain PFAS. PFAS analyses may be primarily related to drinking water quality compliance, occurrence assessment in source water, forensic analysis of PFAS contamination, and analytical support to PFAS removal. The United States Environmental Protection Agency (EPA) established the drinking water lifetime health advisories of 70 ng/L for PFOA, PFOS or the sum of these two PFAS (2016). The pace of action on PFAS issues varies greatly from state to state. Maximum contaminant levels, notification levels, human health-based values, trigger levels, or action levels have been established, recommended, or proposed for individual PFAS in several states (e.g., NJ, NH, NY, CA, MI, MN, OH, OR, etc.) or as sums of selected PFAS in a few states (e.g., VT, MA, WI, etc.). Several other states have also developed statewide action plans. In addition, EPA’s proposed fifth Unregulated Contaminant Monitoring Rule (UCMR5) will include 29 PFAS that can be analyzed by a combination of EPA Methods 537.1 and 533.

EPA 537.1 and 533 are two drinking water methods using liquid chromatography/tandem mass spectrometry (LC/MS/MS) combined with solid-phase extraction (SPE). They are also often used in analyzing surface water and groundwater both directly associated with or disassociated with finished drinking water. However, it is largely unclear how well these two methods can be used to analyze PFAS in various non-potable water matrices. There are few studies supporting such applications.

In this work, we will present the results from a PFAS round robin study conducted by four Eurofins laboratories. The main purpose of this study was to evaluate the performance of EPA 537.1 and 533 for use with both potable and non-potable water matrices. This study includes native and fortified reagent water, finished drinking water, surface (lake and river) water, ground well water, and treated wastewater. The presentation will focus on the accuracy, precision, and challenges of these two methods used for both potable and non-potable water PFAS analyses. The results have indicated that both methods are generally applicable for surface water evaluation. However, specific non-potable water matrices may post a challenge to meet the quality control acceptance criteria as described in the methods.