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根据荧光染料在金纳米粒子表面的能量转移,本文建立了一种具有高灵敏和高选择性半胱氨酸分析方法.研究表明,通过静电作用吸附在柠檬酸根包被的金纳米粒子表面的阳离子荧光染料如罗丹明B分子在受光激发时,发生从荧光染料到金属纳米微粒的能量转移,导致荧光染料的荧光猝灭.但当体系中存在半胱氨酸时,由于半胱氨酸与金纳米粒子之间具有更强的共价作用,罗丹明B分子远离金纳米粒子表面,降低了能量转移效率,使得罗丹明B的荧光得到恢复.恢复的荧光强度与0.025～4.5μmol/L半胱氨酸呈很好的线性关系,检测限为8.0nmol/L(3σ),而其他十九种基本氨基酸的响应非常微弱.
According to the energy transfer of fluorescent dyes on the surface of gold nanoparticles, a highly sensitive and highly selective cysteine assay was developed in this paper.It is shown that the electrostatic adsorption of cations on the surface of citrate-coated gold nanoparticles Fluorescent dyes, such as rhodamine B, undergo energy transfer from the fluorescent dye to the metal nanoparticle when excited by light, resulting in fluorescence quenching of the fluorescent dye, but when cysteine is present in the system, cysteine and gold The more covalent interaction between the nanoparticles, the rhodamine B molecules away from the surface of the gold nanoparticles, reducing the energy transfer efficiency, making rhodamine B fluorescence was restored. The restored fluorescence intensity and 0.025 ~ 4.5μmol / L cysteine A linear relationship was found for the amino acids with a detection limit of 8.0 nmol / L (3σ), while the response of the other 19 basic amino acids was very weak.