One 2 mL flame-sealed ampule yields in excess of 1.5 L after dilution. The diluted standard is certified for 44 analytes spiked at 20--400 ng/L . The sample is designed for LC/MS/MS methods for analyzing wastewater, specifically EPA Method 1633 and 1633A, ASTM Method D8421-21, and SW-846 Method 8327. PFOS, PFHxS, NEtFOSAA and NMeFOSAA are made using standards which include both branched and linear isomers. The assigned value presented on the Certificate of Analysis for these compounds is the total isomer concentration. This product is a replacement for 598 (PT), 403 (CRM), and 403QR (QR).