Method Development for Ultrashort-Chain and Short-Chain PFAS Analysis in Potable and Non-Potable Waters

Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by S. Liang, M. Chang
Restek Corporation, 110 Benner Circle, Bellefonte, PA, 16823, United States


Contact Information: [email protected]; 814-353-1300

ABSTRACT

While the current standard tests are focusing on the PFAS with carbon chains of C4 and up using reverse-phased liquid chromatography (RPLC) methodologies, more studies have shown the prevalence and high levels of ultrashort-chain (USC) PFAS (C1-C3) in environmental aquatic systems (e.g., rain, river, ground waters, and wastewaters). USC PFAS are very polar compounds contributed to at least 40% of total PFAS detected in environmental waters, with trifluoroacetic acid (TFA) being the most abundant and difficult to be analyzed by conventional RPLC. Therefore, a simple and reliable LC method is necessary to fulfill the need for standard analytical workflows of USC PFAS.
This presentation will discuss a proposed ASTM method development (WK80687) for C1 to C4 carboxylate and sulfonate PFAS analysis in tap waters, bottle waters, and wastewaters. A direct injection method was evaluated by accuracy and precision analysis implementing a unique hybrid HILIC/ion exchange column. A critical challenge was encountered for TFA quantification due to its ubiquitous contamination in reagent solvents used in the lab. The reverse osmosis water was identified to be the cleanest one for TFA contamination and was used for the preparation of all standard solutions. A fast LC method with isocratic elution was established for accurate quantification of all C1 to C4 PFAS. The isotopically-labeled C4 compounds, M3PFBS and M4PFBA, were implemented as internal standards to correct various matrix effects in different water samples. This workflow provides convenient setup and high throughput analysis for the lab interested in adding ultrashort-chain compounds to PFAS assay in both potable and non-potable waters.