Determination of PFAS in Environmental Wastewater Samples by Combustion Ion Chromatography: Collaboration Results from the EPA Draft Method 1621

Per- and Polyfluoroalkyl Substances (PFAS) in the Environment
Poster Presentation

Prepared by N. Rumachik, T. Christison, C. Shevlin
Thermo Fisher Scientific, 1214 Oakmead Pkwy, B10, Sunnyvale, CA, 94085, United States


Contact Information: [email protected]; 408-481-4625

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) have been widely used for decades in products such as lubricants, foaming agents, fire-fighting solutions, and anti-moisture films for their surfactant properties. Though they are extensively used throughout industrial, consumer, pharmaceutical, and electronics markets, PFAS compounds are persistent organic pollutants. They pose an environmental contamination concern, impacting freshwaters and oceans, soils and air, and even aquatic and terrestrial food cycles. While the toxicity of most PFAS compounds is unknown, a wide range of adverse health outcomes have been reported because of their bioaccumulation. Additionally, public awareness and concerns have grown as PFAS compounds have been reported in various foods. Together, these environmental and health concerns have led to the regulation of PFAS content in many waters and consumer products, creating a need for analytical screening methods to identify and quantitate PFAS contaminants in these samples.

Pyrohydrolytic combustion ion chromatography (CIC) is a useful analytical tool to determine organic fluorine in samples, as it is known to eliminate the sample matrix and to convert all halogens to halide anions for subsequent suppressed conductivity detection. Here, we present results from our lab obtained as part of the U.S. EPA draft Method 1621 collaboration study. For this study, 100 mL of wastewater was adsorbed onto granulated activated carbon, pyrolyzed under inert gas at 1050 C, hydrolyzed with oxygen and water vapor, and aerated into deionized water. Fluoride was separated from the water dip and other anions on a Dionex™ IonPac™ AS24 anion-exchange column using an electrolytically generated hydroxide gradient and detected by suppressed conductivity detection. We achieved recoveries of 80-120%, demonstrating method accuracy, as well as method detection limits of 2.5 ug/L, demonstrating method sensitivity. These data helped finalize Method 1621 and develop formal performance criteria for the determination of adsorbable organic fluorine in aqueous matrices.