Bifunctional silicon quantum dots sensing platform for selective and sensitive detection of p-dihydroxybenzene with double signals

Being awfully harmful to the environment and human health, the sensitive and selective determination of p-dihydroxybenzene (p-DHB) in environmental water is of great significance. However, the similar structures and properties of p-DHB with catechol (CC; one p-DHB isomer) make the selective and reliable determination of p-DHB from CC in environmental waters being still a formidable challenge. In this manuscript, by preparing CC stabilized silicon quantum dots (C-SiQDs) via a simple hydrothermal process and using C-SiQDs simultaneously as a catalyst and fluorescence indicator, a novel nanosensing platform was successfully developed to selectively and sensitively detect p-DHB with double signals: fluorescence and colorimetric. For detecting p-DHB, C-SiQDs could catalyze the oxidation of p-DHB to form benzoquinone (BQ), an intermediate, which lead to the color change from pale yellow to dark brown and the efficient quenching the fluorescence of C-SiQDs. While for CC in samples, it could not contact C-SiQDs surface due to the great steric hindrance effect from CC on quantum dots surface, thus restricting the oxidation of CC and production of BQ, and leading that the obtained C-SiQDs have no response towards CC. Meanwhile, the developed nanosensor could also avoid various other possible interferences. Under optimized conditions, wide linear ranges (from 0.01 mu M to 50.0 mu M) and low detection limits (4.0 nM) were obtained for p-DHB. The simple and reliable C-SiQDs-based double signals proposal demonstrated to be potentially applicable for the highly selective and sensitive detection of trace p-DHB in various environmental water samples.