Particle-Size Modulated MOFs for Fluorescent PFAS Sensing
6 affiliations
- 1Department of Civil Engineering
- 2University of Arkansas
- 3Department of Chemistry
- 4Rutgers University - Newark
- 5Southern Methodist University
- 6Department of Chemistry and Biochemistry
Abstract
Per- and polyfluoroalkyl substances (PFAS) require sensitive and accessible detection technologies to complement conventional laboratory-based analytical methods. Metal-organic frameworks (MOFs) have emerged as promising fluorescence sensing platforms owing to their high surface areas, tunable pore environments, and versatile host-guest interactions. To date, efforts to improve MOF-based PFAS sensing have primarily focused on framework chemistry and pore engineering, while the role of particle size has remained largely unexplored. Here, we systematically investigate the influence of particle size on PFAS fluorescence sensing using NU-1000 as a model fluorescent MOF platform. A series of NU-1000 particles with sizes ranging from approximately 300 nm to 10 μm were synthesized while maintaining comparable crystallinity, porosity, morphology, and chemical composition. Fluorescence measurements revealed a pronounced particle-size dependence, with smaller particles exhibiting substantially enhanced responses toward perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorodecanoic acid (PFDA). Reducing the particle size from 2 μm to 300 nm lowered the limits of detection by approximately one-half, from 311.4 to 153.8 ppb for PFOA, from 282.0 to 145.3 ppb for PFOS, and from 615.4 to 269.4 ppb for PFDA. Mechanistic investigations showed that the observed size effect does not arise from differences in PFAS uptake. Instead, decreasing particle size increases the surface-to-volume ratio, resulting in a larger fraction of surface-accessible Zr6 adsorption sites and emissive TBAPy linkers that induces more efficient fluorescence signal generation. Consequently, PFAS adsorption events are converted into more substantial fluorescence responses despite comparable overall uptake. These findings identify particle size as a previously overlooked design parameter governing MOF-based fluorescence sensing and demonstrate that particle-size engineering offers a simple, effective, and broadly applicable strategy for enhancing sensing performance without altering framework chemistry or pore architecture.
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BibTeX
@misc{chen2026particlesize,
title = {{Particle-Size Modulated MOFs for Fluorescent PFAS Sensing}},
author = {Minshu Chen and Wenjun Liu and Meng Du and Chujun Zhou and Tyler Maddox and Haoyuan Chen and Shang Jia and Lei Guo},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008948/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008948/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Particle-Size Modulated MOFs for Fluorescent PFAS Sensing
AU - Minshu Chen
AU - Wenjun Liu
AU - Meng Du
AU - Chujun Zhou
AU - Tyler Maddox
AU - Haoyuan Chen
AU - Shang Jia
AU - Lei Guo
PY - 2026
DA - 2026/09/16
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008948/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008948/v1
AB - Per- and polyfluoroalkyl substances (PFAS) require sensitive and accessible detection technologies to complement conventional laboratory-based analytical methods. Metal-organic frameworks (MOFs) have emerged as promising fluorescence sensing platforms owing to their high surface areas, tunable pore environments, and versatile host-guest interactions. To date, efforts to improve MOF-based PFAS sensing have primarily focused on framework chemistry and pore engineering, while the role of particle size has remained largely unexplored. Here, we systematically investigate the influence of particle size on PFAS fluorescence sensing using NU-1000 as a model fluorescent MOF platform. A series of NU-1000 particles with sizes ranging from approximately 300 nm to 10 μm were synthesized while maintaining comparable crystallinity, porosity, morphology, and chemical composition. Fluorescence measurements revealed a pronounced particle-size dependence, with smaller particles exhibiting substantially enhanced responses toward perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorodecanoic acid (PFDA). Reducing the particle size from 2 μm to 300 nm lowered the limits of detection by approximately one-half, from 311.4 to 153.8 ppb for PFOA, from 282.0 to 145.3 ppb for PFOS, and from 615.4 to 269.4 ppb for PFDA. Mechanistic investigations showed that the observed size effect does not arise from differences in PFAS uptake. Instead, decreasing particle size increases the surface-to-volume ratio, resulting in a larger fraction of surface-accessible Zr6 adsorption sites and emissive TBAPy linkers that induces more efficient fluorescence signal generation. Consequently, PFAS adsorption events are converted into more substantial fluorescence responses despite comparable overall uptake. These findings identify particle size as a previously overlooked design parameter governing MOF-based fluorescence sensing and demonstrate that particle-size engineering offers a simple, effective, and broadly applicable strategy for enhancing sensing performance without altering framework chemistry or pore architecture.
ER -