S2 EP05 | Finding the Invisible: How Scientists Detect PFAS (From Parts Per Billion to Trillion)

In this episode, we wrap up Season 2 by exploring one of the most important questions in PFAS research: How do scientists detect something they cannot see, smell, or taste? PFAS often exist at incredibly small concentrations, measured in parts per billion or even parts per trillion. To put that into perspective, a single part per trillion is an almost unimaginably tiny amount. Yet scientists can still find and measure these chemicals with remarkable accuracy. Understanding how detection works is the foundation of understanding everything we know about PFAS today. We break down the technology behind PFAS testing, including liquid chromatography mass spectrometry, or LC-MS. This powerful method allows scientists to separate chemicals, identify their unique molecular fingerprints, and measure them at extremely low concentrations. Whether testing water, soil, blood, or plant tissue, LC-MS helps researchers detect contamination that would otherwise remain completely invisible. The episode also explores the challenges of testing, including the fact that there are thousands of PFAS compounds and that even laboratory equipment must be carefully managed to avoid contamination. Most importantly, this episode explains why measurement matters. Detection does not automatically mean danger, but it provides the data needed for research, regulation, and accountability. Without the ability to measure PFAS, many environmental and public health concerns would remain hidden. Advances in testing technology have helped scientists better understand how widespread these chemicals are and have driven important conversations about safety, exposure, and long-term risk. Science makes the invisible visible, and that knowledge helps communities make more informed decisions. In the next episode, we begin Season 3 by focusing on human health and exploring how PFAS enter the body, move through the bloodstream, and interact with different biological systems.