A ratiometric fluorescence probe toward Zn2+ detection in acidic gastric juice sample based on quinoline/carbonized polymer dot

The Zn 2+ level in gastric juice serves as a powerful reference for the distinction of benign/malignant lesions. However, its accurate detection remains challenging due to the complex and highly acidic samples. Herein, a ratiometric fluorescence probe was developed based on quinoline-functionalized carbonized polymer dots (CPDs) for Zn 2+ accurate detection. The probe has two emission bands at 410 nm and 490 nm. The quinoline groups on the CPDs can form coordination bonds with Zn 2+ , enabling specific recognition of zinc ions. Zn 2+ addition can lead to fluorescence quenching of quinoline component of quinoline/CPD probes in simulated gastric fluid samples, while the emission of the CPDs remains almost unchanged. This ratiometric response between emission intensity at 410 nm and 490 nm enables accurate quantitative detection of Zn 2+ . The probe exhibited a detection sensitivity of 4.56 nM for Zn 2+ and demonstrated outstanding selectivity against other metal ions, attributed to its self-calibration capability. This work offers a novel strategy for designing ion sensing platforms and holds great potential for aiding the diagnosis of gastrointestinal diseases.