L-赖氨酸修饰的荧光碳量子点的制备及在钴测定中的应用

以葡萄糖为原料,通过微波法制备了L-赖氨酸修饰的碳量子点(CQDs),研究了该CQDs与钴的荧光猝灭效应并将其应用于钴的测定。通过高分辨电子显微镜(TEM)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)、紫外-可见吸收光谱和荧光光谱等对L-赖氨酸修饰的CQDs进行结构表征分析。结果发现,该CQDs具有较强的荧光特性。条件优化试验表明,在pH 9.70的B-R缓冲体系中,在340nm的光激发下,此CQDs最大荧光发射波长位于420nm处,Co²⁺的质量浓度在0.03~0.60μg/mL及0.60~4.0μg/mL范围内与体系的荧光猝灭强度呈良好的线性关系,相关系数分别为0.9964和0.9918,检出限为3.84ng/mL。将实验方法应用于水样中痕量钴的测定,测定结果与原子吸收光谱法(AAS)基本一致,相对标准偏差(RSD,n=5)为1.7%~2.0%。

Preparation of L-lysine modified fluorescent carbon quantum dots and its application in determination of cobalt

The L-lysine modified fluorescent carbon quantum dots (CQDs) were prepared by microwave method using glucose as the raw material. The fluorescence quenching effect between CQDs and cobalt were investigated for the application in determination of cobalt. The structures of L-lysine modified CQDs were characterized and analyzed by high-resolution transmission electron microscopy (TEM) and X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), ultraviolet-visible absorption spectroscopy and photoluminescence spectroscopy. The results showed that the prepared CQDs had strong fluorescence characteristics. The conditional optimization experiments indicated that the maximum fluorescence emission wavelength of CQDs was located at 420nm in B-R buffer system at pH 9.70 under the excitation wavelength of 340nm. The mass concentration of Co²⁺ in range of 0.03-0.60μg/mL and 0.60-4.0μg/mL had good linear relationship with the fluorescence quenching intensity of system. The correlation coefficient was 0.9964 and 0.9918, respectively. The detection limit of method was 3.84ng/mL. The proposed method was applied for the determination of trace cobalt in water samples. The found results were basically consistent with those obtained by atomic absorption spectrometry (AAS). The relative standard deviations (RSD, n=5) were between 1.7% and 2.0%.