In the present work, a novel metal-organic framework (MOF) fluorescent probe was prepared by post-synthetic modification of MIL-53-NH2(Al) with carboxylatocalix[4]arene (CC[4]A). The introduced CC[4]A could not only enhance the fluorescence performance and the recognition ability of the probe, but also sustain the high stability under UV light and moisture conditions. A method based on the as-synthesized CC[4]A@MIL-53-NH2(Al) probe was established for sensing hippuric acid. The detection limit was determined to be as low as 3.7 μg mL-1. Over the concentration range of 0.005-3 mg mL-1, the calibration curve was obtained with a satisfactory linearity (R2 = 0.993). The method was successfully used for rapid and highly selective direct monitor of hippuric acid in human urine. The sensor had great potential to be used as a simple diagnostic tool for hippuric acid in human urine which is regarded as a biological index of toluene exposure.

中文翻译：

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杯[4]芳烃功能化金属有机骨架探针的设计，用于高灵敏度和选择性监测马尿酸以指示甲苯暴露

在目前的工作中，通过用羧基杯[4]芳烃 (CC[4]A) 对 MIL-53-NH2(Al) 进行后合成修饰，制备了一种新型金属有机骨架 (MOF) 荧光探针。引入的CC[4]A不仅可以增强探针的荧光性能和识别能力，而且可以在紫外光和潮湿条件下保持高稳定性。建立了一种基于合成的CC[4]A@MIL-53-NH2(Al)探针来检测马尿酸的方法。检测限低至 3.7 μg mL-1。在 0.005-3 mg mL-1 的浓度范围内，获得的校准曲线具有令人满意的线性 (R2 = 0.993)。该方法已成功用于快速、高选择性地直接监测人尿中的马尿酸。