A portable logic detector based on Eu-MOF for multi-target, on-site, visual detection of Eu3+ and fluoride in groundwater

Developing a portable analytical device for rapid and visual detection of multiple targeted pollutants in groundwater is very important. In this paper, a novel Eu-MOF was prepared and applied for the highly sensitive and selective detection of Eu3+ and fluoride in groundwater. In the presence of Eu3+, the blue-violet fluorescence at 425 nm of Eu-MOF is greatly quenched because of the aggregation effect caused by Eu3+ combined with the amino functional groups exposed on Eu-MOF. The detection limit of Eu3+ has been determined as (2.481 +/- 0.014) x 10(-7) M according to the 3s rule. Furthermore, the addition of fluoride would replace Eu3+ bound to amino group to induce the fluorescence recovery, and the detection limit of fluoride was calculated to be (1.145 +/- 0.009) x 10(-6) M. The common interfering ions have no influences on the selective detection of Eu3+ and fluoride by Eu-MOF. In addition, the spiked and recovery test indicated that Eu-MOF can be used for detection of Eu3+ and fluoride in real water samples and possess efficient and favorable practicability. More importantly, the logic detectors and paper sensors based on Eu-MOF were designed and fabricated as the portable analytical devices for the visual detection of Eu3+ and fluoride in groundwater. Our research would be beneficial and helpful for the water quality safety and human health guarantee.