Ratiometric fluorescence sensing of triclosan by Lanthanide-Functionalized Metal–Organic frameworks

Abstract

As a widely used antibacterial and antifungal agent in numerous personal care and consumer products, triclosan (TCS) is frequently detected in natural water bodies and has caused serious harm on human health and ecosystems. The quantitative and fast analysis of TCS is thus of paramount significance, however still remains challenging. In recent years, ratiometric fluorescence sensing has attracted vast interests in analyte detection due to the dual emission, which can effectively eliminate interference from environmental factors and improve the detection accuracy. Benefiting from the strong encapsulation capability and structural adjustability, metal organic frameworks (MOFs) are demonstrated to be a perfect platform to construct ratiometric fluorescence sensors. In the present study, we modify a zirconium MOF, UiO-67-bpy, to be a ratiometric fluorescence sensor by introducing Eu3+ and carbon dots sequentially via the post-synthetic method. The obtained hybrid system, CDs@Eu/UiO-67-bpy, shows two well separated emission peaks. With the addition of TCS, the red fluorescence from Eu3+ at 611 nm decreases while the blue fluorescence from carbon dots at 412 nm remains unchanged, resulting an excellent ratiometric response. Linear relationships of the fluorescence ratio (F412/F611) against the concentration of TCS are acquired in both low and high concentration range with detection of limit as low as 0.53 and 2.3 μM, respectively. Moreover, satisfactory recoveries of TCS levels from CDs@Eu/UiO-67-bpy are achieved in various water samples and personal care products. The composite of CDs@Eu/UiO-67-bpy also displays a fluorescence color changing from red to blue responsive to different concentration of TCS, demonstrating great potential in practical application of CDs@Eu/UiO-67-bpy for visualized monitoring TCS.