Sensitive Fluorescent Sensor for Hydrogen Sulfide in Rat Brain Microdialysis via CsPbBr3 Quantum Dots

The instability and insolubility of perovskite quantum dots in aqueous solution prohibit applications in polar solvents. As a highly toxic gas pollutant and also an endogenous gaseous signaling molecule existing in a variety of physiological processes, hydrogen sulfide (H₂S), with high selectivity and high specificity, detection is of great significance. In this study, a simple device has been designed to separate H₂S from aqueous solution and CsPbBr₃ quantum dots (CsPbBr₃ QDs) have been used as the detection probe to develop a novel fluorescent sensor for rapid H₂S detection. The addition of hydrogen sulfide to the phosphoric acid solution results in the escape of H₂S from the aqueous sample and hence it passing into the n-hexane solution containing CsPbBr₃ QDs, resulting in the quenching of the fluorescence of CsPbBr₃ QDs. The fluorescence intensity of the system has a linear relationship with the concentration of H₂S in the range of 0-100 μM with the detection limit of 0.18 μM. The proposed system has been applied to detection of H₂S in rat brain microdialysate with satisfying results. The potential mechanism regarding the quenching of fluorescence from CsPbBr₃ QDs by H₂S has been studied as well.