A highly water-stable dual-emission fluorescent probe based on Eu-loaded MOF for the simultaneous detection and quantification of Fe and Al in swine wastewater.

A novel dual-emissive Eu-loaded metal-organic framework (MOF) is designed and successfully fabricated by introducing 2-hydroxyterephthalic acid (HBDC-OH) and Eu ions into an UiO-66-type MOF material. The obtained MOF, here referred to as EuUCH, exhibits dual emission at 450 and 614 nm, and both emissions are quite stable in aqueous media in the pH range of 4-11. EuUCH is characterized by a high selectivity and sensitivity toward Fe and Al, which yield different responsive modes. The two emissions of EuUCH are quenched by Fe; by contrast, only the emission at 450 nm is quenched by Al showing a ratiometric fluorescence signal. More importantly, as there is no clear interference between the signals of Fe and Al, EuUCH is successfully utilized for the simultaneous detection of Fe and Al in their mixtures. In addition, the simultaneous quantification of Fe and Al is achieved in more complicated swine wastewater with good recoveries. This work provides a water-stable dual-emissive probe and the possibility to achieve the simultaneous quantification of Fe and Al in complicated environment wastewater.