纳米银溶胶稳定性的考察及其对表面增强拉曼光谱检测的影响

目的: 考察纳米银溶胶的稳定性与影响其稳定性的因素,以及其稳定性对于表面增强拉曼光谱检测的影响。 方法: 用电子透射显微镜和zeta电势对银溶胶及加入电解质或酸碱后的银溶胶进行了表征,并用zeta电势对不同温度下不同时间段的银溶胶进行了稳定性考察。选择了苏丹红III、盐酸西布曲明、盐酸吡格列酮3个化合物做为探针分子,对比了它们在分散的银溶胶及沉降后的银溶胶中的表面增强拉曼光谱的差异。并比较分析了它们在不同温度及不同时间段测定的表面增强拉曼光谱。 结果: 在温度较低的环境下,2个月之内的银溶胶基本能保持稳定,2个月之后,稳定性显著下降。而在温度较高的环境下,银溶胶极易沉降失活。加入电解质或酸碱后,银溶胶颗粒迅速凝聚。分散的银溶胶对于苏丹红III、盐酸西布曲明、盐酸吡格列酮3个化合物均有较理想的增强效应,沉降后的银溶胶对3个化合物的增强均不明显。环境温度变化对于表面增强拉曼光谱检测的影响基本可以忽略。表面增强拉曼光谱测定的最佳时间为样品与银胶混合后的1 h内,时间过长,纳米沉降使得光谱信号显著减弱。 结论: 外来酸碱对银溶胶稳定性的影响比一般的电解质要大。时间和温度也是影响溶胶稳定性的重要因素之一。分散的银溶胶具有较强的拉曼增强活性,沉降后的银溶胶增强活性明显下降。

Objective: To study the stability of nano silver particles and analyze its influence factors,as well as the influence of its stability on surface-enhanced Raman spectroscopic detection. Methods: Transmission electron microscope and zeta potential were applied to characterize the silver sol and the silver sol after adding electrolyte or acid/base.The stability of different time points of the silver sol at different temperatures with zeta potential was studied.Sudan red III,sibutramine hydrochloride and pioglitazone hydrochloride were selected as probe molecular,the differences of surface-enhanced Raman spectroscopic in the dispersing silver particles and the precipitated silver particles between these three compounds were compared,and their surface-enhanced Raman spectroscopic determined in different temperature and different time points were comparatively analyzed. Results: The silver sol basically remained stable within two months in low-temperature environment.Two months later,the stability of silver sol declined significantly;the silver sol was extremely easy to subside and lost activity in high-temperature environment.The nano silver particles aggregated rapidly after adding electrolyte or acid/base.The dispersing silver particles showed better enhancement effect Sudan red III,sibutramine hydrochloride and pioglitazone hydrochloride.The enhancements of the precipitated silver particles to the three compounds were not obvious.The effects of environmental temperature changes could be ignored for surface-enhanced Raman spectroscopic detection.The best time of surface-enhanced Raman spectroscopic determination was within one hour after the mixing of the sample with the silver sol,the nano settlement made the spectral signal significantly weakened afterward. Conclusion: The influence of external pH on the stability of the silver sol is larger than the average of the normal electrolyte.Time and temperature also importantly affect the stability of silver sol.The dispersing silver particles has stronger Raman enhancement activity,and the enhanced activity significantly decreases when the silver particles precipitate.