A simple cleft shaped hydrazine-functionalized colorimetric new Schiff base chemoreceptor for selective detection of F− in organic solvent through PET signaling: Development of a chemoreceptor based sensor kit for detection of fluoride

Additi Roy Chowdhury, Biswajit Gopal Roy, Saibal Jana, Thomas Weyhermuller, Priyata Banerjee

Novel colorimetric hydrazine-functionalized Schiff base chemoreceptor [N1N3bis(perfluorobenzylidene)isophthalahydrazide] NBPBIH has been prepared for selective detection of F. In this receptor more NH and CN units are incorporated for better colorimetric responses as compared to systems having lesser number of such units. NBPBIH turns from colorless to dark yellow on exposure to F. The detection event is well supported by UV–vis, fluorescence, 1H and 19F-NMR like spectrophotometric and cyclic voltammetric studies in DMSO because of enhanced fluorescence responses, higher Stokes shift value and for its less toxic nature compared to other solvents. Quenching of fluorescence is explained with photoinduced electron transfer mechanism (PET). The binding constant of NBPBIH with F is around 0.84 × 105 M−1 and limit of detection of F is found 1.42 × 10−5 M. Our concern is also to address fluorosis: an issue related to global health problem, affecting millions of common people. It is noteworthy that the existing diagnostic and treatment options are of huge expenses. As an artefact, chemoreceptor assisted simple prototype for detecting excessive fluoride in sample solution has been designed and developed which has potential and good prospect to be applied as a low cost affordable diagnostic kit for fluorosis in largely affected countries like China, India and several others.

The MS analysis was carried out using Advion Expression® CMS ESI.