ASTM D8421 PFAS in Water Samples: a Single Laboratory Verification

Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Presented by W. Lipps
Prepared by N. Iwasa1, W. Lipps2, R. Marfil-Vega2, J. Nagata1
1 - Shimadzu Corporation, SCOE, Kyoto, Kyoto, 604-8442, Japan
2 - Shimadzu, , , United States


Contact Information: [email protected]; 410-910-0884

ABSTRACT

Per- and Polyfluoroalkyl substances (PFAS) are used in a wide range of consumer products and industrial applications due to their excellent heat resistance and water repellency. While PFAS have useful features, they can pollute surface water, groundwater, soil, and air in various regions around the world, and have adverse effects on human health. This has led to a worldwide tightening of regulations on PFAS. Among regulatory targets, PFAS analysis in aqueous matrices is the most regulated, and various analytical methods have been developed. ASTM D 8421 -22 is a standard test method for determination of PFAS in aqueous matrices by LC/MS/MS, and short-chain to long-chain PFAS are specified as the compounds to be measured. ODS columns, commonly used in reversed-phase chromatography, have weak column retention of compounds with short carbon chains, making it difficult to obtain good peak shapes under some conditions. Dilution with water is the easiest way to improve the chromatography, but PFAS analysis requires high sensitivity. In this study, we evaluated the effect of column dimensions by the cosolvation and direct injection method with reference to ASTM D 8421 -22. Shim-pack GIST-HP C18 3 mm, 50 mm x 2.1 mm used as reference column, and the optimum dimensions were investigated. When a column with a small particle size was used, the mixing of the sample solvent and the mobile phase was suppressed, and the peak shape deteriorated due to the suppression of multichannel diffusion. On the other hand, with longer column length and thicker inner diameter, axial diffusion improves symmetry at the column exit and improves peak shape. In addition, a change in peak shape was observed by examining the mobile phase composition. With the optimized conditions, short-chain to long-chain PFAS (C3 - C 14) could be measured sensitively with good peak shape.