Benchtop 1H and 19F NMR as an analytical tool for monitoring photocatalytic degradation

Le résumé fourni par la source

Background Reliable monitoring of photocatalytic degradation requires analytical techniques capable of delivering selective and molecular-level information. In this study, low-field benchtop NMR spectroscopy is evaluated as an accessible tool for monitoring the degradation of model pollutants under LED irradiation at 371 nm using supported TiO 2 photocatalysts. Results A dedicated LED–NMR setup was developed to enable both ex situ and in situ UV irradiation within a 60 MHz NMR spectrometer using TiO 2 -coated quartz rods. The effective NMR detection zone was experimentally defined to prevent magnetic perturbations induced by solid inserts, and experimental parameters were evaluated to ensure adequate signal-to-noise ratio tailored to both time-limited acquisition and millimolar-scale reaction monitoring. Both 1 H and 19 F nuclei were investigated, enabling complementary monitoring of protonated and fluorinated species. Conclusion The analytical performance of the method was assessed using three representative model pollutants: methylene blue (MB), 5-fluorouracil (5-FU), and perfluorooctanoic acid (PFOA). Benchtop NMR enabled reproducible monitoring of degradation profiles, detection of transformation products, and differentiation between adsorption phenomena and photolysis. These results demonstrate that LED-assisted benchtop NMR constitutes a valuable proof-of-concept for the in situ monitoring of model photocatalytic processes.

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