Design and evaluation of highly sensitive luminescent terbium sensor for hypochlorite in water

A novel terbium 2-methyl-benzoimidazole-5-carboxylic acid complex was prepared and incorporated into silica matrix (tetraethoxysilane) using a mild sol-gel technique. We then successfully fabricated a terbium luminescent xerogel, which maintained intense green emission even in pure water. The emission was rapidly (similar to 1 s) quenched by ClO(-) (detection limit 10(-5) M) but not NO(3)(-), CH(3)COO(-), F(-), Cl(-), Br(-), I(-), CO(3)(-), and OH(-). The selectivity appears to be due to the high vibrational energy of ClO(-) as well as its strong oxidation capability.