以中药材-玄参原药为碳源,通过高温煅烧法制备得到荧光碳量子点。碳量子点水溶液在270 nm波长的激发下,其荧光的最大发射波长位于418 nm处。向荧光碳量子点溶液中加入硝酸根离子(N O3-),将猝灭其荧光强度,基于此建立了碳量子点作为荧光探针测定N O3-的一种新方法。在最优实验条件下,当N O3-摩尔浓度为0.4~80 μmol/L时,信号与N O3-的浓度成良好的线性关系,检出限为65 nmol/L。添加5.0 μmol/L和50.0 μmol/L的N O3-溶液到实际水样进行加标回收实验时,回收率为98.0%~104.0%。

With the Chinese medicinal material Radix Scrophulariae as a carbon source, the fluorescent carbon quantum dots are prepared by the high temperature calcination method. The carbon quantum dots solution under the excitation at 270 nm wavelength has the maximal fluorescent light emission wavelength at 418 nm. The fluorescent light intensity of the carbon quantum dots solution can be effectively quenched by the introduction of the nitrate ions (N O3-). Based on this, a novel method for detecting N O3- is developed using carbon quantum dots as the fluorescent probes. Under the optimal experimental conditions, the signal shows a good linear relationship with the concentration of N O3- when this concentration is in the range from 0.4 μmol/L to 80 μmol/L. The limit of detection is 65 nmol/L. When the 5.0 μmol/L or 50.0 μmol/L N O3- solution is added to the real water samples for the standard adding recovery experiment, the recovery rate is in the range from 98.0% to 104.0%.