A novel turn-on fluorescent probe for the multi-channel detection of Zn2+ and Bi3+ with different action mechanisms

Abstract

A novel multifunctional sensing material, RSPT, incorporating rhodamine B hydrazide, a Schiff base, and a phenolic hydroxyl group into triazine, was identified and prepared. After the molecular structure was characterized by FTIR, ¹H NMR, mass spectra and element analysis, it was notably found that there were multichannel turn-on fluorescent responses to Zn²⁺ and Bi³⁺, i.e., a strong fluorescence emission at 481 nm in DMF–water (99/1, v/v) for Zn²⁺ with a color change from colorless to light yellow-green, while an increased fluorescence emission at 580 nm in CH₃CN–water (99/1, v/v) for Bi³⁺ with a color change from colorless to red. Their different action mechanisms for the RSPT–Zn²⁺ and RSPT–Bi³⁺ complexes were investigated and confirmed by means of fluorescent titration, binding constant, Job's plot curve, ¹H NMR titration, and theoretical simulation. RSPT would be a promising turn-on fluorescent chemo-dosimeter for multichannel detection of Zn²⁺ and Bi³⁺ with a detection limit of 3.0 nM for Zn²⁺ and 8.6 nM for Bi³⁺.