A sensitive naphthalimide‐thiomorpholine derivative as a turn‐on fluorescent probe for monitoring hypochlorite ions

Abstract Hypochlorite ion (ClO − ) plays a critical role in sterilization processes within biological and environmental aqueous systems, but its excessive levels can lead to harmful oxidative reactions associated with various human diseases. In this study, we present Naph‐HOCl, a novel water‐soluble naphthalimide–thiomorpholine derivative, as a turn‐on fluorescent probe for the selective and sensitive detection of ClO − . Upon exposure to ClO − , the probe exhibits a rapid fluorescence enhancement at 563 nm, demonstrating excellent selectivity over other reactive oxygen species, biothiols, and common ions. The probe demonstrates a low detection limit of 287 nM and a high signal‐to‐noise ratio (s/n) of 42, indicating strong potential for analytical monitoring of ClO − . The exploration of its applicability in real sample analysis will be carried out in future studies.