Rapid and facile ratiometric detection of CO32− based on heterobimetallic metal-organic frameworks (Eu/Pt-MOFs)

- A heterobimetallic metal-organic frameworks (Eu/Pt-MOFs) is synthesized.
- Dual-emission with a broad band of linkers and Eu3+.
- A ratiometric fluorescent sensor toward carbonate ions (CO32−).
- Low detection limit of Eu/Pt-MOFs for CO32− was 0.021 μM.
- Good stability in aqueous environment, selectivity, fast detection time to water samples.

A ratiometric fluorescent sensor towards carbonate ions (CO32−) based on a heterobimetallic metal-organic frameworks (Eu/Pt-MOFs) have been synthesized under a facile hydrothermal condition. And then the as-synthesized MOFs are characterized by PXRD, FT-IR, TG, fluorescence spectroscopy and its lifetime (τ). The Eu/Pt-MOFs not only shows dual-emission with a broad band centered at about 560 nm and a characteristic emission of Eu3+ but also have good stability in the aqueous solution, which was further used as a novel fluorescence probe for detecting CO32−. With CO32− addition, the luminescence of Eu3+ is enhanced while the broad band is suppressed significantly. The relative intensity ratio of IEu(614)/ILigand linearly with increasing concentration of CO32− with 0.021 μM detection limit, which much lower than the content of carbonate in accordance with the nutritional and hygienic standards and guidelines for quality certification in children's preferable food. Besides, the robust Eu/Pt-MOFs sustain good stability in aqueous environment, excellent selectivity, fast detection time and applying to different water samples. This work makes the direct, rapid and reliable detection of carbonate ions for practical application possible.

A heterobimetallic metal-organic frameworks (Eu/Pt-MOFs) was chosen as proposed system for carbonate ions detection because of its special luminescence and good water-stability.159