A Review of Fluorescent Sensor Development for Ultrasensitive Per- and Polyfluoroalkyl Compound Analysis in Water: Toward in Situ Monitoring Platforms

Anthropogenic per- and polyfluoroalkyl substances (PFAS), valued for their chemical stability, are widely used in industrial and consumer products. Their persistence leads to bioaccumulation, particularly in water, posing significant risks to human health via contaminated water, food, and PFAS-treated products. Although regulations exist, gold standard analysis is time-consuming, complex, and costly, limiting real-time and in situ monitoring. Efficient, field-deployable detection technologies are urgently needed. This review reports an up-to-date and critical assessment of fluorescence-based sensors, often harnessing engineered nanomaterials, for the detection of PFAS in water with a view to portable systems for in situ monitoring. We discuss the photophysical and chemical principles of these sensors and evaluate key performance metrics─including sensitivity, selectivity, response time, and sample preparation─that affect operational efficiency and field portability. Despite challenges such as matrix interference and sensitivity limits, emerging nanomaterial designs and sensor architectures offer promise for robust, practical continuous in situ PFAS monitoring.