Fluorescence “turn on” detection of perfluoroalkyl substances in water

Author: Karen Ly, Department of Chemistry, Biology, and Health Sciences

Mentor: Dr. Zhengtao Zhu, Department of Chemistry, Biology, and Health Sciences

Perfluoroalkyl substances (PFAS) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are commonly used industrially in non-stick, stain resistant, and fire-retardant products. PFAS have earned the “forever chemical” moniker due to their inherent resistance to degradation. This resistance results in their continued persistence in the environment, which have been linked to adverse health effects such as low birth weights, dyslipidemia, and immunosuppression in children. Highly sensitive and selective detection of PFAS is crucial to monitoring of PFAS in water. Current methods of PFAS detection, including HPLC and GC-MS require expensive instrumentation, extensive sample preparation, and long analysis times. Fluorescence detection of PFAS may have advantages over other methods due to the simple sample preparation, high sensitivity and selectivity, low-cost, and portability for on-site analysis. In this research, fluorescence “turn-on” sensor for PFAS is reported. Fluorescence of a dye (eosin Y) is first quenched by formation of a complex with a quencher (e.g. polyethyleneimine, melamine, or metal ions). Adding PFAS to the dye-quencher complex releases the dye due to formation of stronger interactions between PFAS and the quencher, resulting in fluorescence “turn-on”. Different dye and quencher systems are investigated to develop the fluorescence sensor for PFAS. The pH of these systems is also varied to deduce how pH affects formation of complexes between the dye, quencher, and PFAS molecules. Protocol to determine concentration of PFAS in a solution is established and the mechanisms of the fluorescence sensor for PFAS detection are investigated.