This past August, EPA published Draft Method 1633 – Analysis of Per- and Polyfluoroalkyl Substances (“PFAS”) in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS.  Once, finalized, this single laboratory validated method will be available for 40 PFAS compounds (including Perfluorooctanesulfonic acid (PFOS), Perfluorononanoic acid (PFNA), Perfluorooctanoic acid (PFOA), and Perfluorobutanesulfonic acid (PFBS)) in