Abstract:

We synthesize a novel sensing molecule 1-hydroxy-naphthalen-ethyl-3-hydroxy-naphthalen-methyl-benzoimidazo-bromate(J1) which can carry out a single selective colorimetric dual-channel recognition of CN^- in aqueous medium. When F^-, Cl^-, Br^-, I^-, AcO^-, HSO₄^-, ClO₄^- , H₂PO₄^- , SCN^- and CN^- ions were added respectively in sensing molecule J1's DMSO/H₂O(3:2 volume ratio) HEPES(pH=7.2) solution, only CN^- turns the solution from colorless to deep yellow. In the same time, only CN^- among the ions added in sensing molecule J1's DMSO/H₂O(4:1, volume ratio) HEPES(pH=7.2) solution allows the chemosensor responding with a dramatic color change, from colorless to bright yellow. These recognition processes are not disturbed by other negative ions. This indicates that sensing molecule J1 is a good colorimetric recognition receptor of CN^-. The UV-Vis spectrum of sensing molecule J1 has a wide linear range over CN^- concentration from 3.875×10^-4 mol/L to 2.15×10^-2 mol/L with a detection limit of 1.575×10^-7 mol/L. The linear range of the fluorescence of the sensor for CN^- is at the concentration from 0.8×10^-4 mol/L to 1.60×10^-3 mol/L with a detection limit of 4.63×10^-6 mol/L. The sensing molecule J1 has good selection, high sensitivity and strong antidisturbance on CN^- in aqueous medium. Based on sensing molecule J1's high selection on CN^-, we specially prepare test paper which can test CN^- in water in a convenient, fast and accurate way.

Key words: acyl hydrazone compounds, cyanide ion, test paper, fluorescent sensor