A selective proton transfer optical sensor for copper II based on chelation enhancement quenching effect (CHEQ)

2020 
Abstract A novel selective fluorescent sensor for Cu2+ in solution has been developed by means of chelation enhancement quenching effect (CHEQ). The compound N,N′-bis(salycilidene)-(2-(3′,4′-diaminophenyl)benzothiazole (BTS) is reactive to intramolecular proton transfer on the electronic excited state (ESIPT) presenting fluorescence emission in the blue region with very large Stokes shift (8794 cm−1). Spectroscopic titration experiments indicate that not only the fluorescence quenching but also of the ESIPT reaction allowed naked eye detection as a paper strip-based sensor. This chemosensor showed to be selective to Cu2+ among 13 other cations. The sensor:Cu2+ ratio was determined by both Job and Benesi-Hildebrand plots as 1:2. In addition, the binding between sensor and metal was investigated by 1H NMR, FTIR and HRMS in order to elucidate the formed complex and corroborate the results of BTS:Cu2+ ratio. The binding constant was also found as 3.0 × 1010 mol−2 L2 at 25 °C. The detection and quantification limits were also obtained as 32 ppb and 108 ppb, respectively.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    52
    References
    10
    Citations
    NaN
    KQI
    []