A naked-eye visible colorimetric and ratiometric chemosensor based on Schiff base for fluoride anion detection

• HNA is a dual-platform colorimetric and ratiometric chemosensor. • The LOD of HNA for detecting F − is low to 0.61 μM. • HNA can be used for detecting F − in real samples. A dual-platform colorimetric and ratiometric chemosensor, namely 6-(2-hydroxynaphthalen)- N -n-butyl-naphthalimide ( HNA ), based on Schiff base constructed from N -n-butyl-4-amino-1,8-naphthalimide and 2-hydroxy-1-naphthaldehyde has been designed and fabricated for detecting fluoride anion (F − ) in DMSO solution. HNA is a colorimetic and ratiometric probe with superior selectivity and sensitivity. The color changes of HNA from yellow to purple was observed by the naked eyes in the presence of F − . The absorbance in the UV-Vis spectra of HNA was decreasing in 422 nm, while gradually increasing in 583 nm by adding F − . The limit of detection (LOD) of HNA for detecting F − is low to 0.61 μM and the binding model of HNA and F − is in 3:2 stoichiometry. Meanwhile, HNA can be used to detect F − in real samples. Finally, the mechanism of HNA for the detection of F − was investigated. The present work indicated that HNA would be a superior potential chemosensor in monitoring F − selectively and sensitively. HNA is a dual-platform colorimetric and ratiometric chemosensor with superior selectivity and sensitivity. The color changes of HNA from yellow to purple in DMSO solution was observed by the naked eyes in the presence of F − .