A highly colorimetric and ratiometric fluorescent probe for the detection of fluoride ions using test strips

In this work, a colorimetric and ratiometric chemosensor NP-OTBDPS, 4-(tert-butyldiphenylsilyloxy)-N-butyl-naphthalimide, was designed and synthesized. NP-OTBDPS can serve as a ‘naked-eye’ colorimetric indicator for F⁻ and ratiometric detection of F⁻ in aqueous systems can also be realized. The probe shows a high selectivity for fluoride against various interferents and the detection limit can be as low as 0.07 μM. More importantly, by observing color and fluorescence changes, the test strip coated with NP-OTBDPS provides an economical and convenient tool for the detection of fluoride ions.