Forensic PFOA

The evolution of PFAS analysis has seen dramatic increases in compound lists over the last several years (Barzen-Hanson et al. 2017). During the same time period, advances in instrumentation have resulted in lower detection limits for both legacy and next-generation PFAS, driven by more stringent state regulations. The availability of additional analytical and isotopically labeled PFAS standards have also increased which greatly improves the identification and quantitation of PFAS in the environment. These developments enable PFAS analytical laboratories to deliver higher quality data which assists the regulators and understand the scope of PFAS at their sites. 

One recent area of interest in PFAS analysis is the distribution of linear to branched isomers. Differences in production lead to different distribution of the linear and branched isomers. For example, PFAS produced using the electrochemical fluorination (ECF) process have both linear and branched isomers with even and odd chain lengths. Meanwhile, PFAS produced by the fluorotelomerization (FT) process creates mainly linear isomers with a fluorinated and nonfluorinated carbon chain (Benskin et al., 2007, Schulz et al., 2020, ITRC, 2020). Eurofins has supported the analysis of linear and branched isomers for which a certified technical standard is commercially available. These technical standards contain known amounts of both linear and branched isomers and facilitate reporting of Branched/Linear and the Total sum of these isomers, affectionately known as “B/L/T PFAS.”

While BLT PFAS are nothing new for predominant PFAS researchers and laboratories alike, Eurofins is pleased to support a more refined BLT approach for PFOA. The characterization of PFOA in the environment has been under increased scrutiny and this advanced BLT analysis is designed specifically to support forensic investigations. The differentiator in this approach includes monitoring of additional ions of PFOA that delve into the speciation of branched PFOA isomers while unique calibration strategies facilitate the precise quantitation of linear to branched ratios of PFOA. 

Eurofins has been a pioneer in this field, conducting the necessary method development to support existing consent orders, research studies and the government in their method development efforts over the past few years. With over 20 years of experience and 500,000 PFAS samples analyzed, Eurofins has the knowledge and expertise to navigate this approach and knows how to generate defensible and meaningful data for you.

References:

_{Barzen-Hanson KA, Roberts SC, Choyke S, Oetjen K, McAlees A, Riddell N, McCrindle R, Ferguson PL, Higgins CP, Field JA. Discovery of 40 Classes of Per- and Polyfluoroalkyl Substances in Historical Aqueous Film-Forming Foams (AFFFs) and AFFF-Impacted Groundwater. Environ Sci Technol. 2017 Feb 21;51(4):2047-2057. doi: 10.1021/acs.est.6b05843.}

_{Benskin JP, De Silva AO, Martin JW. Isomer profiling of perfluorinated substances as a tool for source tracking: a review of early findings and future applications. Rev Environ Contam Toxicol. 2010;208:111-60. doi: 10.1007/978-1-4419-6880-7_2.}

_{Interstate Technology & regulatory Council (ITRC). 2020. PFAS Technical and Regulatory Guidance Document and Fact Sheets PFAS-1. Washington, D.C.: Interstate Technology & regulatory Council, PFAS Team. https://pfas-1.itrcweb.org/.}

_{Schulz K, Silva MR, Klaper R. Distribution and effects of branched versus linear isomers of PFOA, PFOS, and PFHxS: A review of recent literature. Sci Total Environ. 2020 Sep 1;733:139186. doi: 10.1016/j.scitotenv.2020.139186.}