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

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.