Selective Ligand-Doped Liquid Crystal-Based Sensing Platform for Detection of ClO(–) Ions in Aqueous Media

[Image: see text] The liquid crystal (LC) detection platform has been fabricated for the detection of hypochlorite ions (ClO(–)) in aquatic solutions. In this system, an imine consisting of the ligand (E)-2-((4-(diethylamino)-2-hydroxybenzylidene)amino)-5-methoxybenzenesulfonic acid (MBA) was doped in 4-cyano-4′-pentyl biphenyl as a selecting LC for ClO(–). When immersing the platform in a solution containing ClO(–), hypochlorite appears to react with the imine bond in the MBA, and cause it to cleave, which eventually disrupts the direction of LC and causes a dark-to-bright conversion of the LC image. The detection limit for ClO(–) is 0.05 μM. This sensory platform was unresponsive to NO(3)(–), BrO(3)(–), CH(3)COO(–), CO(3)(2–), and PO(4)(3–) ions. Our sensing platform also detected ClO(–) in piped water. Since this sensory platform is colored under ambient light, it is easy for regular operators, and it can be used as a mobile tool for monitoring water quality anywhere.