A selective fluorescence quenching method for the determination of trace hypochlorite in water samples with nile blue A

摘要

Recently, growing concern has been paid to the sensitive and selective determination hypochlorite because of its crucial roles in our daily life. In this paper, a simple, sensitive, selective spectrofluorimetric method was applied to detect the hypochlorite. Upon reaction of the probe with ClO-, a fluorescence quenching was observed. The method was shown to be highly selective for ClO-, and exhibited real time response as well as linear relationship to ClO- concentration, and hypochlorite could be detected at low micromolar levels in aqueous solution. The linear response range of hypochlorite (R-2 = 0.9994) was from 0.13 to 25 mu mol/L. The detection limit (3 sigma/k) was 0.04 mu mol/L, which was lower than that of previously mentioned. The accuracy and reliability of the method was further ensured by recovery studies via a standard-addition method, with percentage recoveries in the ranges of 95.0-104.8%, 963-102.6% and 97.8-102.5, respectively. Additionally, the quenching mechanism was discussed. Judging from temperature, fluorescence lifetime, UV-visible absorbance spectra, quenching mechanism was proved static quenching. This method was finally used to detect the hypochlorite in local water samples. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.