A cellulose-based near-infrared fluorescent probe for ratiometric imaging and visual monitoring of ClO− in water via smartphone

Cellulose is the most abundant renewable biomass resource on Earth, with good biodegradability and biocompatibility. In this study, a novel cellulose-based near-infrared fluorescent probe MN@NIR for ClO − detection was developed by amination modification of microcrystalline cellulose (MCC), followed by the introduction of naphthalimide fluorophores and dicyanoisophorone groups. The probe MN@NIR exhibits excellent fluorescence properties with dual-emission peaks at 543 nm and 690 nm, the latter falling within the near-infrared (NIR) window. It shows highly specific “ratiometric” and “colorimetric” fluorescence responses to ClO − , with the fluorescence color gradually changing from red to blue as the ClO − concentration increases. Notably, the probe demonstrates a rapid response time (2 min) and excellent selectivity and anti-interference properties. The fluorescence film prepared from the probe shows outstanding specificity for ClO − and has been successfully applied to the visual monitoring of ClO − in water samples. Furthermore, this study combines smartphone image analysis technology to develop a G/B color ratio- ClO − monitoring platform, providing a new solution for the quantitative analysis of ClO − concentrations in water and on-site rapid detection.