Hypochlorite ion (ClO-/HClO) is a reactive oxygen species that plays a vital role in biological systems and daily life. The accurate detection of ClO- is critical for disease prevention and environmental monitoring. Therefore, it is necessary to develop highly sensitive probes. In this study, we report a visual fluorescence-enhanced HClO/ClO- probe CN-TPE-PEG1900, which was obtained by grafting poly (ethylene glycol) monomethyl ether 1900 with tetraphenylethylene (TPE) as the fluorescent parent. The fluorescence intensity of a solution containing CH3OH/H2O (30 μM, v/v, 1/4, PBS, pH = 7.4) and the probe CN-TPE-PEG1900 was increased by 9 times at 525 nm due to the presence of ClO-. The color of the probe CN-TPE-PEG1900 solution changed from yellow to colorless after reaction with ClO-. The limit of detection (LOD) of the probe CN-TPE-PEG1900 was 5.48 × 10–8 mol/L. In addition, it had a high fluorescence quantum yield of 51.27 %, a large Stokes shift of 165 nm, good water solubility, and high water sample recovery rates. The calculated data, 1H NMR, mass spectrometry, DLS, and SEM results were combined to deduce the recognition mechanism of the probe CN-TPE-PEG1900 for ClO-. Thus, the presence of ClO- facilitated the cleavage of the double bond in CN-TPE-PEG1900, thereby separating the water-soluble poly (ethylene glycol) chain from TPE through oxidative cleavage. Moreover, this led to the formation of TPE-CHO, which was less water-soluble and more prone to aggregation, resulting in fluorescence enhancement at 525 nm. Meanwhile, the process also caused a blue shift in the emission wavelength and a change in the color of the probe solution.
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