A Multimode Optical Sensor for Highly Selective and\nSensitive Detection of Hypochlorous Acid in Water and Body Fluid

Hypochlorous acid (HClO), as an important\nreactive oxygen species\n(ROS), plays a crucial role in our daily life and in biological systems,\nand its convenient and accurate detection is significant and imperative.\nIn this work, a self-calibrated multimode optical sensor for convenient\nand accurate HClO detection was elaborately fabricated based on a\nmultifunctional metal−organic framework platform with catalytic\nactive metal nodes, fluorescent responsive bridging ligands, and intrinsic\npores for functional molecule accommodation. The sensor shows not\nonly turn-on and ratiometric fluorescence response but also color\nchange in response to HClO. The detection limits are as low as 16.9,\n17.3, 66.5, and 63.2 nM for ratiometric fluorometry, absorbance-based\ncolorimetry, and smartphone-based fluorescenceand\ncolor analysis, respectively. The accuracy and practicability of this\nsensor were also demonstrated by the detection of hypochlorous acid\nin actual water and body fluid samples, and the recovery rates ranged\nfrom 97.8 to 103.8%.