A Handy Chemical Sensor Based on Benzaldehyde and Imidazo[1,2-a]pyridine Mixture for Naked-eye Colorimetric and Fluorescent Detection of F

• Published in: Journal of fluorescence Vol. 33; no. 6; pp. 2381 - 2390
• Main Authors: Mei, Xin, Li, Hui, Pu, Shouzhi
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2023; Springer Nature B.V
• Subjects: Analytical Chemistry; Benzaldehyde; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedicine; Biophysics; Biotechnology; Chemical sensors; Chemoreceptors; Colorimetry; Fluorescence; Fluorides; Imines; Mass spectrometry; NMR; Nuclear magnetic resonance; Pyridines; Structural analysis; Titration; Schiff base; Fluorescence; Naked-eye; F
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-023-03195-2

Upon the Schiff base condensation reaction of imidazo[1,2-a]pyridine-2-carbohydrazide and 2,5-dihydroxybenzaldehyde, a bimodal colorimetric and fluorescent chemosensor 1o for assaying fluoride (F − ) in DMSO was synthesized. The characterization of 1o structure was obtained by 1 H NMR, 13 C NMR and MS.The structure of 1o was characterized by 1 H NMR, 13 C NMR and MS. Under the presence of various anions, 1o could be applied for naked-eye and fluorescent detection of F − (naked eye: colorless to yellow; fluorescence: dark to green) and displayed promising performance, such as high selectivity and sensitivity, as well as a low detection limit. Upon calculation, the detection limit of chemosensor 1o for F − was 193.5 nM, which is well below the allowed maximum value of F − (1.5 mg/L) by WHO. As the intermolecular proton transfer mechanism induced "turn-on" fluorescent signal and naked-eye color change of F − to 1o through deprotonation effect, which was confirmed by Job's plot curve, mass spectrometry and 1 H NMR titration. Alternatively, the chemosensor 1o can be effectively manufactured into test strips to detect fluoride in solid state, which is user-friendly with no additional equipment required. Graphical Abstract