A ratiometric fluorescent probe for hypochlorous acid determination: Excitation and the dual-emission wavelengths at NIR region

An interesting ratiometric fluorescent probe with unique optical performance was reported in this work. By modifying on the bridge-head of heptamethine cyanine chromophore with an N-phenyl-N’-ethylene amine thiourea substituent as a chemodosimetric recognition unit, the probe exhibited ratiometric fluorescent response towards hypochlorous acid (HClO). Upon addition of HClO, the absorbance spectra showed a great red shift as large as 150nm from 650nm to 800nm. Employing the isosbestic absorption point at 730nm as an excitation wavelength, a ratiometric fluorescent sensing mode with two long emission wavelengths at 760nm and 820nm was acquired, and thus the probe displayed significant behavior with both the excitation wavelength and the dual-emission wavelengths located at NIR (650–900nm) region exclusively. Also, the probe showed excellent performance in high sensitivity and good selectivity towards HClO over other reactive oxygen species and a wide variety of coexist species in biological pH condition and had been successfully used to detect hypochlorous acid in serum samples and tap water samples. [Display omitted] •A ratiometric fluorescent heptamethine cyanine-based probe for HClO was developed.•HClO was measured with the excitation and the dual-emission wavelengths at NIR Region.•The mechanism relies on HClO-promoted desulfurization to afford a guanidine group.•The probe showed high sensitivity and good selectivity towards HClO.