Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece.
Anal Chim Acta. 2010 Jun 11;669(1-2):45-52. doi: 10.1016/j.aca.2010.04.046. Epub 2010 May 17.
Citrate-modified gold nanoparticles were found to undergo size and color transition upon interaction with alkaline earth metals. At low concentrations, metal ions coordinate with AuNPs via citrate boding inducing aggregation which results in size increase as evidenced by the decrease in their plasmon bandwidth. As the concentration increases further, color transition from red to blue is observed which is no longer attributed to aggregation but to specific ion adsorption phenomena. The response of gold nanoparticles to these changes linearly depends on cation concentration in both the UV and Vis regions, a feature that was exploited for the assessment of alkaline earth metal concentrations in water samples. Based on these findings, the modification of the surface properties of metal-coated AuNPs were investigated with regard to their potential influence on the catalytic oxidation of luminol by periodate. Interestingly, a significant amplification of the CL emission signal was recorded when metal ions were associated with AuNPs, even for chemiluminescence "inert" cations like calcium and magnesium. The analytical implications of these findings for the improvement of CL sensitivity and its potential analytical applications are also discussed.
柠檬酸修饰的金纳米粒子在与碱土金属相互作用时会发生尺寸和颜色转变。在低浓度下，金属离子通过柠檬酸结合与 AuNPs 配位，导致聚集，从而导致尺寸增加，这可以通过等离子体带宽的减小来证明。随着浓度的进一步增加，观察到从红色到蓝色的颜色转变，这不再归因于聚集，而是归因于特定的离子吸附现象。金纳米粒子对这些变化的响应在紫外和可见区域内都线性地取决于阳离子浓度，这一特性被用于评估水样中碱土金属的浓度。基于这些发现，研究了金属包覆的 AuNPs 表面性质的修饰，以研究其对高碘酸盐催化氧化鲁米诺的潜在影响。有趣的是，当金属离子与 AuNPs 结合时，即使对于化学发光“惰性”阳离子如钙和镁，也记录到 CL 发射信号的显著放大。还讨论了这些发现对提高 CL 灵敏度及其潜在分析应用的分析意义。
