A simple fluorescein derived colorimetric and fluorescent ‘off–on’ sensor for the detection of hypochlorite

Abstract

In this work, we have successfully provided a novel strategy to probe for ClO⁻. The strategy is based on a specific reaction promoted by ClO⁻: namely, hypochlorite oxidizes the amino group in probe 1 to an imine. Interestingly, in the presence of ClO⁻, a colorless solution of probe 1 turned pink with a maximum absorption band at 479 nm, and a 150-fold fluorescence enhancement at 553 nm was found. Probe 1 is highly selective to ClO⁻ among other anions with a detection limit of 0.023 μM. The membrane-permeable probe 1 was successfully demonstrated for monitoring ClO⁻ in cultured HeLa cells. Therefore, probe 1 can be used for detection in practical samples. Probe 1 developed herein makes possible the use of organic complexes containing amines for designing fluorescence probes for ClO⁻.