Wu Zhihao, Yang Huan, Pan Shuang, Liu Hui, Hu Xiaoli
College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.
ACS Sens. 2020 Jul 24;5(7):2211-2220. doi: 10.1021/acssensors.0c00853. Epub 2020 Jul 13.
Ratiometric fluorescence has drawn extensive attention owing to its self-calibration property. However, it is difficult to obtain appropriate fluorescent materials that can be excited under one excitation and possess well-resolved signals simultaneously. In this work, with the optical properties of the fluorescence of carbon dots (CDs) and the second-order scattering (SOS) of ZIF-90 (zeolitic imidazole frameworks-90) nanoparticles, the synthesized CDs@ZIF-90 can be applied to phosphate (PO) ratiometric detection. The fluorescence of CDs is greatly suppressed through encapsulating CDs into ZIF-90. Nevertheless, the SOS is quite obvious due to the high scattering intensity of large size ZIF-90. The competitive coordination between PO and the metal node of ZIF-90 decomposes CDs@ZIF-90, leading to the restoration of fluorescence and the diminution of SOS. On the basis of the PO-induced ZIF-90 decomposition and CD release, a novel method for PO ratiometric detection is developed through the dual-signal response of the fluorescence scattering. Under the optimal condition, the method shows a linear range from 1.0 to 50.0 μmol L with a detection limit of 0.23 μmol L. Furthermore, the probes are employed to assess PO in practical aqueous samples successfully. Compared with the traditional approach, which only records fluorescence signals, the method reported here provides a new strategy to design ratiometric sensors by fluorescence and scattering.
比率荧光因其自校准特性而受到广泛关注。然而，很难获得能在单一激发下被激发且同时具有良好分辨信号的合适荧光材料。在这项工作中，利用碳点（CDs）荧光的光学性质和ZIF-90（沸石咪唑框架-90）纳米颗粒的二阶散射（SOS），合成的CDs@ZIF-90可应用于磷酸盐（PO）的比率检测。通过将CDs封装到ZIF-90中，CDs的荧光被极大地抑制。然而，由于大尺寸ZIF-90的高散射强度，SOS相当明显。PO与ZIF-90的金属节点之间的竞争性配位分解了CDs@ZIF-90，导致荧光恢复和SOS减弱。基于PO诱导的ZIF-90分解和CD释放，通过荧光散射的双信号响应开发了一种用于PO比率检测的新方法。在最佳条件下，该方法的线性范围为1.0至50.0 μmol L，检测限为0.23 μmol L。此外，该探针成功用于实际水样中PO的评估。与仅记录荧光信号的传统方法相比，本文报道的方法为通过荧光和散射设计比率传感器提供了一种新策略。
