Michael and Schiff-Base Reactions-Assisted Fluorescence Sensor Based on the MOF Nanosheet Microspheres for the Effective Discrimination and Detection of Hydroquinone and Catechol

A novel sensing platform was constructed for the recognition and identification of dihydroxybenzene isomers based on the MOF-0.02TEA fluorescence sensor with the morphology of nanosheet microspheres through coordination modulation. Based on the sensing principle that the amino group on the MOF-0.02TEA can make the Michael reaction with o -benzoquinone and p -benzoquinone, which were individually the oxidation intermediate of catechol and hydroquinone, the fluorescence intensity of MOF-0.02TEA could be quenched through the inner filter effect (IFE) without the interference from resorcinol. Besides, catechol and hydroquinone could be further distinguished with the assistance of the Schiff-base reaction by introducing o -phenylenediamine (OPD) to the detection system. The MOF-0.02TEA sensor exhibited good selectivity, and the detection limits for catechol and hydroquinone were 90.5 nmol/L and 0.52 μmol/L (S/N = 3), respectively. Moreover, the sensor could be used for the determination of dihydroxybenzene isomers in tap water and lake water.