Per- and polyfluoroalkyl substances (PFAS) are a group of harmful organic compounds that are very persistent in structure. What this means is PFAS compounds accumulate in the environment over time as they do not break down easily. This makes it a concern to regulate and test these compounds as they have been shown to have adverse effects. One of the most common ways that someone would come in contact with PFAS is through drinking water. There are two notable EPA regulated methods that laboratories can use to analyze PFAS compounds, EPA method 533 and 537.1. When evaluating how to handle these methods in your lab there are some key differences in how to approach PFAS testing. See our earlier blog extracting perfluorinated compounds from drinking water – why is it so challenging?