Fluorescence-enhanced detection of hypochlorite based on in situ synthesis of functionalization-free carbon spheres

Hypochlorite (ClO^-) exposure has been confirmed to be associated with many serious diseases. Although abundant organic molecule-based probes have demonstrated high sensitivity and selectivity for ClO^- response, they often suffer from limitations including tedious preparation steps, poor water solubility, and the use of toxic solvent. In this work, a novel fluorescent sensor based on carbon spheres (CS) synthesized by solvothermal method was presented for ClO^- detection. In the presence of ClO^-, the obtained micro-size CS that initially displayed very weak fluorescence experienced a significant fluorescence enhancement in the blue channel, and a linear response range of 2-110 μM with detection limit of 10.7 nM could be achieved. In addition to proposed mechanism verification, a field visualization platform based on smartphone was designed to monitor hypochlorite in real environmental water samples to demonstrate its potential in portable detection.