A highly reusable fluorescent nanofilm sensor enables high-performance detection of ClO2

As the most effective disinfectant, the safe-use of ClO2 is based on proper concentrations. A big challenge in the determination of ClO2 lies in reusability owing to its strong oxidative property. Herein, we report for the first time a nanofilm-based fluorescent sensor towards the high-performance detection of ClO2. The nanofilm was prepared via interfacially confined dynamic covalent condensation of a fluorescent o-carborane derivative (CB-2CHO) and calix[4]arenetetrahydrazide (CATH). The nanofilm as obtained is smooth and uniform. The thickness can be tuned at least from 80 nm to 400 nm. Meanwhile, the nanofilm is photochemically stable, and shows a Stocks shift of 193 nm. A fluorescent sensor constructed with the nanofilm depicted fast, sensitive, selective, and fully reversible sensing to ClO2 vapor in air. Moreover, non-invasive detection of the chemical in aqueous phase with a detection limit of similar to 0.85 mg/L was realized via vapor sampling from the headspace of the solution. The linear range is from a few to 5000 mg/L.

Automated summary

A nanofilm-based fluorescent sensor for high-performance detection of ClO2 has been reported for the first time in this study. The sensor exhibits fast, sensitive, selective, and reversible sensing to ClO2 vapor in air, and can also achieve non-invasive detection of ClO2 in aqueous phase.