A colorimetric and fluorescence sensor based on biphenolic-dansyl derivative for specific fluoride ion detection

ABSTRACT

2ʹ-(2-((4-(methylthio)phenyl)amino)-2-oxoethoxy)-[1,1ʹ-biphenyl]-2-yl 5(dimethyl amino)naphthalene-1-sulphonate (1) was synthesised and used as a F⁻ ion sensor. The selectivity of sensor 1 with various anions (F⁻, Cl⁻, Br⁻, CH₃COO⁻, C₆H₅COO⁻ and H₂PO₄⁻) in DMSO was evaluated by ¹H NMR, UV-visible and fluorescence study. For ¹H NMR, an amide proton of sensor 1 disappeared due to the deprotonation reaction upon addition of F⁻ ion. On the contrary, the proton signal of HF₂⁻ emerged at 16.11 ppm. Upon addition of F⁻ ion, sensor 1 showed a new absorption band at 300 nm and the solution turned colourless. For fluorescence response, sensor 1 exhibited the enhancement of emission intensity at 434 nm with slight blue shift when titrated with F⁻ ion. These results suggest that sensor 1 possessed high sensitivity and selectivity towards F⁻ ion detection. In addition, the sensor 1 test strip coated on TLC plates and filter papers were demonstrated for specific detection F⁻ ion.

Graphical abstract

KEYWORDS:

• Anion sensor
• deprotonation reaction
• F⁻ ion detection

Disclosure statement

No potential conflict of interest was reported by the authors.

Conflicts of interest

The authors declare no conflict of interest.

Supplementary material

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Additional information

Funding

This research is supported by Kasetsart University Research and Development Institute, and Department of Chemistry, Kasetsart University, and the Center of Excellent for Innovation in Chemistry (PERCH-CIC), Commission on Higher Education, Ministry of Education.