Concentrations of per- and polyfluoroalkyl substances (PFAS) from validation experiments and custom sample analysis by U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) Laboratory Code 9660, December 2020 to March 2022

This data release contains concentration and isotope-dilution standard (IDS) recovery data from individual samples that are summarized and interpreted in the U.S. Geological Survey (USGS) Techniques and Methods (T&M) Report "Determination of Per- and Polyfluoroalkyl Substances in Water by Direct Injection of Matrix-Modified Centrifuge Supernatant and Liquid Chromatography-Tandem Mass Spectrometry with Isotope Dilution". This includes results from method validation experiments and quality control data collected in conjunction with custom sample analysis for customers using USGS National Water Quality Laboratory (NWQL) Laboratory Code 9660 between December 15, 2020 and March 2, 2022. Results in the T&M Report are presented as statistical summaries of data from multiple related samples, the individual sample data that underlie those summaries are presented here.