金纳米“关-开”型荧光探针测定三价铁离子和L-赖氨酸

Turn-off-on sequential detection of Fe^(3+) and L-lysine based on gold nanoclusters

以N-乙酰-L-半胱氨酸为配体,通过硼氢化钠还原氯金酸合成单层修饰的、水溶性良好的金纳米簇(AuNCs),采用TEM、FTIR、UV-Vis和PL等分析测试技术对AuNCs的形貌特征和光学性质进行了考察。实验结果表明,该AuNCs具有优良的荧光性能,当激发波长为520 nm时,其最大发射波长为620 nm。研究发现,Fe^(3+)能强烈猝灭AuNCs的荧光,而加入L-赖氨酸后,AuNCs的荧光被恢复。AuNCs的荧光猝灭和恢复的程度与Fe^(3+)和L-赖氨酸的浓度在一定范围内呈线性关系,Fe^(3+)和L-赖氨酸的线性范围分别为11.65~163.35μmol·L^(-1)和13.36~266.64μmol·L^(-1),检出限分别为1.65μmol·L^(-1)和1.28μmol·L^(-1)。本研究建立了一种基于AuNCs荧光的“关-开”型传感体系依次用于Fe^(3+)和L-赖氨酸的检测,该方法具有简单、快速、准确度高、灵敏度高、选择性好等优点。

Monolayer modified gold nanoclusters(AuNCs)with good water solubility were synthesized by reducing chlorauric acid with sodium borohydride,using N-acetyl-L-cysteine(NAC)as ligand.The morphology and the optical properties of AuNCs were investigated by various characterization techniques.The maximum emission wavelength is 620 nm with the excitation wavelength of 520 nm,indicating that AuNCs have excellent fluorescence properties.It was found that the fluorescence of AuNCs was strongly quenched by Fe^(3+),and was restored afer further adition of L^(-1)ysine.The fluorescence quenching degee and recovery degree of AuNCs were linearly related to the concentration of Fe^(3+) and L^(-1) ysine in a certain range,respectively.The linear ranges of Fe^(3+) and L^(-1) ysine were 11.65~163.35μmol L^(-l )and 13.36~266.64μmol:L^(-1),and the detection limits were 1.65μmol·L^(-1) and 1.28μmol·L^(-1),respectively.Therefore,a"turn-off-on"fluorescence sensing system based on AuNCs was established for sequential detection of Fe^(3+)and L^(-1) ysine,which has the advantages of simplicity,rapidity,high accuracy,high sensitivity and good selectivity.