谷氨酸钠碳纳米颗粒的荧光光谱及量子产率测定 Measurement of Fluorescence Spectra and Quantum Yield of Carbon Nanoparticles Made from Monosodium Glutamate

本论文主要以高温热解谷氨酸钠得到的荧光碳纳米颗粒(Glu-FCN)为研究对象，对其荧光光谱及其量子产率进行研究。结果显示：一方面，Glu-FCN存在pH依赖性，当pH在3.0到9.0之间时它的荧光强度最强，而其他范围荧光较弱；另一方面，此荧光碳纳米颗粒水溶液发光位置稳定，最佳激发波长为338 nm和发射波长为391 nm，荧光稳定性极佳。在中性环境下，Glu-FCN水溶液的荧光强度和浓度之间存在很好的线性关系，线性范围在0.2~50 μg/mL，检出下限为0.2 μg/mL。最后，以硫酸奎宁溶液为参比，测量了Glu-FCN在不同激发波长下的荧光量子产率，在最佳激发波长338 nm处的荧光量子产率高达51.5%，适合作为荧光标记物使用。 In this article, fluorescent carbon nanoparticles (Glu-FCN), made by monosodium glutamate pyro-lysis, have been researched, mainly including measurements of Glu-FCN fluorescent spectra and quantum yields. On one hand, pH dependence has been shown to be present in Glu-FCN according to our works. The fluorescence intensity is pretty low when surrounding pH is less than 3.0 or over 12.0. In contrast, it will become quite high when the pH is between 3.0 and 9.0. On the other hand, luminous position of Glu-FCN is very fixed. Optimal excitation and emission wavelengths are respectively located at 338 nm and 391 nm in a stable state. Importantly, good linear relationship exists between fluorescence intensity and concentration of Glu-FCN neutral aqueous solutions. The linear range is 0.20 - 50.0 μg/mL, with 0.20 μg/mL limitation. Eventually, quantum yields of Glu-FCN have been determined using quinine sulfate as a reference under different excitations. And Glu-FCN quantum yield is concluded to be as high as 51.5% under the optimal excitation (338 nm), implying its feasibility for being a fluorescent marker.