Developing a fluorescent probe for UO(2)(2+), which is resistant to interference from other ions such as Cu(2+) and can be applied in acidic and high-water systems, has been a major challenge. In this study, a "turn-off" fluorescent probe for triamine-modified flavonoid derivatives, 2-triphenylamine-3-hydroxy-4H-chromen-4-one (abbreviated to HTPAF), was synthesized. In the solvent system of dimethyl sulfoxide:H(2)O (abbreviated to DMSO:H(2)O) (v/v = 5:95 pH = 4.5), the HTPAF solution was excited with 364 nm light and showed a strong fluorescence emission peak at 474 nm with a Stokes shift of 1...