石墨烯量子点荧光探针测定肾上腺色腙

通过高温裂解柠檬酸合成了水溶性石墨烯量子点(GQDs),并应用钝化剂PEG2000进行修饰,提高了GQDs的量子产率。应用荧光光谱、紫外-可见光谱、红外光谱对其发光特性进行了研究,测定了荧光寿命。实验发现,在p H=7.40的Tris-HCl缓冲液中,肾上腺色腙(CBZC)对GQDs荧光强度有明显的猝灭作用。基于此提出了以GQDs为探针测定肾上腺色腙的新方法。实验考察了缓冲溶液用量、缓冲溶液种类、量子点浓度、反应时间以及表面活性剂等多种因素对反应体系的影响。当量子点浓度为2.3×10-3mol/L时,肾上腺色腙浓度在4.0×10-7~1.2×10-5mol/L(0.995 6)范围内与荧光猝灭值ΔF呈良好的线性关系,方法检出限为1.5×10-7mol/L,相对标准偏差为0.15%(n=5,c=4.0×10-6mol/L)。该方法对于样品中肾上腺色腙含量测定的回收率为97.46%~101.6%。通过测定温度对猝灭常数的影响以及紫外-可见吸收光谱的变化确定了二者的猝灭过程和相互作用力类型。

Detection of Carbazochrome by Graphene Quantum Dot Fluorescence Probe

Water-soluble graphene quantum dots (GQDs) were synthesized by the pyrolysis of citric acid. Its fluorescent quantum yield was remarkly increased by PEG2000 modified. The luminescence characteristics of GQDs were studied by fluorescence spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy as well as the fluorescence lifetime. A novel method for quantitative determination of trace carbazochrome (CBZC) was developed based on the fluorescence quenching of GQDs in pH 7.40 Tris-HCl buffer solution. A wide range of reaction parameters, such as concentration of GQDs, reaction time, surfactant, sorts and amount of buffer was examined. The screening results show that the ΔF was linearly related with the carbazochrome concentration from 4.0×10^-7 to 1.2×10^-5 mol/L(0.995 6) with the detection limit of 1.5×10^-7 mol/L. The relative standard deviation is 0.15% (n=5, c=4.0×10^-6 mol/L), when the concentration of GQDs is 2.3×10^-3 mol/L. The method has been used for the determination of carbazochrome in samples with the recoveries of 97.46%-101.6%. The interaction mechanism and main sorts of binding force between GQDs and carbazochrome were investigated by the temperature effect on the quenching constants and UV-visible absorption spectrometry.