Selective fluorescence signaling of hypochlorite in tap water by oxidative hydrolysis of sulfonhydrazone

A new hypochlorite-selective fluorescence signaling probe based on the sulfonhydrazone of 2-acetyl-6-methoxynaphthalene was investigated. The probe was easily prepared by the simple one-step reaction of 2-acetyl-6-methoxynaphthalene with p-toluenesulfonylhydrazide. The probe exhibited off/on-type fluorescence signaling behavior toward hypochlorite in aqueous solution via hypochlorite-triggered oxidative hydrolysis of the sulfonhydrazone to yield strongly fluorescent 2-acetyl-6-methoxynaphthalene. Selective hypochlorite signaling over other common oxidants with a large fluorescence enhancement (76-fold) was possible, with a detection limit of 2.0 x 10(-8) M. Hypochlorite signaling was not affected by the presence of other common metal ions or representative anions. As a practical application, the methoxyacetylnaphthalene sulfonhydrazone probe was used to determine hypochlorite levels in a tap water sample using a standard smartphone as the detection tool. (C) 2016 Elsevier B.V. All rights reserved.