In this work, the carbon dots (CDs) were prepared by one-pot hydrothermal method with chitosan as a carbon source and hydrogen peroxide as an oxidant, this route is a novel, simple and green. The prepared CDs has a relatively high photoluminescence (PL) quantum yield (QY) (18.9%) and good water solubility. CdTe quantum dots (CdTe QDs) possess the characteristic of responding to pH rapidly. So a ratiometric fluorescent probe for measuring pH was constructed using the prepared CDs and CdTe QDs. Under the excitation of 330 nm, the probe shows dual (blue and red) emission with peaks at 430 and 600 nm, respectively. When the pH of the solution changes, the blue fluorescence intensity of the CDs remains stable as a reference signal, while the red fluorescence intensity of CdTe QDs changes accordingly. This method has obvious pH-sensitive feature, stable fluorescence properties, and a great linear relationship with pH values in the range of pH 3.0–11.0. What is more, the method can monitor proton-producing enzyme-catalyzed reactions by acting as a ratiometric pH probe.

在这项工作中，以壳聚糖为碳源，过氧化氢为氧化剂，通过一锅水热法制备了碳点（CDs），这是一种新颖，简单，绿色的方法。制备的CD具有相对较高的光致发光（PL）量子产率（QY）（18.9％）和良好的水溶性。CdTe量子点（CdTe QDs）具有快速响应pH的特性。因此，使用制备的CD和CdTe QD构建了用于测量pH的比例荧光探针。在330 nm的激发下，探针显示出双色（蓝色和红色）发射，并分别在430和600 nm处出现峰。当溶液的pH值变化时，CD的蓝色荧光强度作为参考信号保持稳定，而CdTe QD的红色荧光强度也随之变化。该方法具有明显的pH敏感特性，稳定的荧光特性，并且与pH值在3.0至11.0范围内呈线性关系。而且，该方法可以通过充当比例式pH探针来监控产生质子的酶催化的反应。