Ultratrace PFAS Detection Using Amplifying Fluorescent Polymers

Abstract

Per-and poly(fluoroalkyl) substances (PFAS) are environmentally persistent pollutants that are of growing concern due to their detrimental effects at ultratrace concentrations (ng• L −1 ) in human and environmental health. Suitable technologies for on-site ultratrace detection of PFAS do not exist and current methods require complex and specialized equipment, making the monitoring of PFAS in distributed water infrastructures extremely challenging. Herein, we describe amplifying fluorescent polymers (AFPs) that can selectively detect perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at concentrations of ng•L −1 . The AFPs are highly fluorinated and have poly(p-phenylene ethynylene) and polyfluorene backbones bearing pyridine-based selectors that react with acidic PFAS via a proton-transfer reaction. The fluorinated regions within the polymers partition PFAS into polymers, whereas the protonated pyridine units create lowerenergy traps for the excitons, and emission from these pyridinium sites results in red-shifting of the fluorescence spectra. The AFPs are evaluated in thin-film and nanoparticle forms and can selectively detect PFAS concentrations of ∼1 ppb and ∼100 ppt, respectively. Both polymer films and nanoparticles are not affected by the type of water, and similar responses to PFAS were found in milliQ water, DI water, and well water. These results demonstrate a promising sensing approach for on-site detection of aqueous PFAS in the ng•L −1 range.

Analysis of needs for enforcement of PFAS in articles and chemical products

“…Recently, the use of amplifying luorescent polymers (AFPs) for a selectively detection of PFOA and PFOS at concentrations of ng/L was shown (Concellon et al, 2023). The AFPs are highly luorinated and have selectors that react with acidic PFAS via a proton-transfer reaction, results in shifting of the luorescence spectra and LOD around 1 µg/L.…”

J‐Aggregate‐Triggering BODIPYs: an Ultrasensitive Chromogenic and Fluorogenic Sensing Platform for Perfluorooctanesulfonate

“…Nevertheless, there have been limited studies on the development of fluorescent probes for assaying PFOS and/or PFOA in water. [19][20][21][22][23][24][25][26][27][28][29][30][31][32] In particular, the lack of reactivity of these chemicals precludes selective chemical reaction-based chemodosimeter designs. Many reported fluorescent sensors are limited by poor water solubility, high background signals and low sensitivity (3-5-fold signal increase), leading to unappealing detection limits.…”

“…Visual indicators based on fluorescence or color changes that could be used without complicated process or prior training would be particularly appealing for rapid on‐site presumptive assays. Nevertheless, there have been limited studies on the development of fluorescent probes for assaying PFOS and/or PFOA in water [19–32] . In particular, the lack of reactivity of these chemicals precludes selective chemical reaction‐based chemodosimeter designs.…”

Fast and Selective Luminescent Sensing by Langmuir–Schaeffer Films Based on Controlled Assembly of Perylene Bisimide Modified with A Cyclometalated AuIII Complex

“…The performance of FFSs relies on designing innovative sensing luminophores and fabricating efficient adlayer structures for mass transfer [2–4] . Common methods used to fabricate luminescent films include spin‐coating, [5] self‐doping, [6] drop‐coating, [2] electrospinning, [7] molecular gel‐based self‐assembly, [8] and liquid‐air polymerization, [9] but the packing models of luminophores on adlayer have not been clearly investigated. The Langmuir–Blodgett/Schaeffer (LB/LS) technique, a unique method for controlling molecular assembly, allows the formation of highly ordered monomolecular film on a solid substrate [10,11] .…”