Molecule-Probed Raman Spectroscopy for Femtogram-per-Liter Level Per- and Polyfluoroalkyl Substances Detection

Per- and poly-fluoroalkyl substances (PFAS) have received significant attention due to their persistence in the environment. Because of their accumulative nature, even trace amounts can adversely impact human health and ecosystems. Here, we present Molecule-Probed Raman Spectroscopy (MPRS), an ultra-sensitive, low-cost, and fast method that can achieve the femtogram-per-liter detection of PFAS, surpassing any existing methods by at least four orders of magnitude. In contrast to existing Raman Spectroscopy monitoring the spectrum of PFAS, MPRS monitors changes in the Raman spectrum of molecular probes, methyl group (-CH ₃ ) on polydimethylsiloxane, upon PFAS capture. MPRS succeeds in detecting multiple individual PFAS in water and monitoring PFAS in complex matrices such as surface water and human blood. We also demonstrated the feasibility of on-site monitoring of PFAS using a portable Raman spectrometer. Beyond its transformative detection capability, MPRS establishes a new analyte detection paradigm, paving the way for innovative material systems and instruments.