New Reference Materials Released to Support EPA Method 1633 for PFAS Testing

LGC Standards has announced the release of new 13C-labelled per- and polyfluoroalkyl substances (PFAS) reference materials designed for use with United States Environmental Protection Agency (EPA) Method 1633, according to a press release issued by the company (1). These materials include two isotope-labelled internal standard mixtures and a range of single compound solutions. Their purpose is to help laboratories improve calibration, consistency, and accuracy when testing for PFAS across water, soil, and biological samples.

PFAS are a large, diverse group of synthetic chemicals used since the 1940s in consumer products and industrial applications. They are valued for their resistance to heat, water, and oil, which makes them useful in nonstick cookware, waterproof clothing, firefighting foams, food packaging, and electronics. Chemically, PFAS contain multiple carbon–fluorine bonds, making them highly stable and resistant to degradation. Because of this persistence, they are often called “forever chemicals.”

PFAS are environmentally widespread, contaminating soil, surface water, groundwater, and even drinking water. Human exposure occurs mainly through ingestion (contaminated water, food, or packaging), inhalation, and dermal contact. Once in the body, PFAS can bioaccumulate, with half-lives ranging from years to decades depending on the compound.

Health studies have linked certain PFAS (such as PFOA [perfluorooctanoic acid] and PFOS [perfluorooctane sulfonate]) to adverse effects, including increased cholesterol, immune suppression, thyroid disease, liver damage, developmental issues, and certain cancers. In response, many countries have restricted or phased out legacy PFAS, though thousands of replacement compounds remain in use. Ongoing research and regulation aim to better understand their risks and to develop safer alternatives.

To address the need for a harmonized testing procedure, the EPA, in collaboration with the U.S. Department of Defense (DoD), developed EPA Method 1633, which is now superseded by EPA Method 1633A. This liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was released in December 2024 (EPA 820R24007) and is the first PFAS method validated across multiple laboratories. EPA Method 1633 covers 40 PFAS analytes and applies to a wide range of matrices, including wastewater, groundwater, surface water, landfill leachate, soils, sediments, biosolids, and fish or shellfish tissue.

According to the LGC Standards press release, the newly launched materials are specifically aligned with EPA Method 1633 (1). They can improve data quality by compensating for matrix effects, reducing calibration requirements, and minimizing variability introduced during sample preparation or analysis.

In addition to the mixtures, the company offers a wider range of single 13C-labelled compound solutions, designed for laboratories that require flexibility when developing or validating PFAS testing workflows.

Reference materials are essential for analytical chemistry, particularly when dealing with compounds such as PFAS that are found at trace concentrations. By providing well-characterized calibration standards, laboratories can generate data that is reproducible, which is necessary for compliance with regulatory frameworks.

The release of new 13C-labelled PFAS materials represents ongoing efforts to align laboratory capabilities with the requirements of EPA Method 1633. It also reflects the growing demand for high-quality standards as more authorities move toward enforcing strict PFAS monitoring programs.

Reference

(1) LGC Standards. LGC Standards launches new 13C-labelled PFAS reference materials to support EPA Method 1633 workflows [Press release]. September 29, 2025.