Trace Elements Speciation Research Laboratory, Environmental and Analytical Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, India; Department of Basic Science, Madanapalle Institute of Technology, Madanapalle 517 325, Andhrapradesh, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Dec;116:539-45. doi: 10.1016/j.saa.2013.07.077. Epub 2013 Aug 6.
A facile rapid green eco-friendly method to synthesize gold nanoparticles (Au NPs) of tunable size using aqueous Terminalia arjuna fruit extracts has been demonstrated herein. Formation of Au NPs was confirmed by Surface Plasmon Resonance (SPR) study at 528 nm using UV-visible spectrophotometer. The time of reduction, size and morphological variations of Au NPs were studied with varying quantities of T. arjuna fruit aqueous extracts. Synthesized Au NPs were characterized using UV-visible spectroscopy, Fourier transformed infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and Energy dispersive X-ray spectroscopy (EDAX). Polyphenols responsible for reduction of Au(3+) to Au(0) were identified using High Performance Liquid Chromatography (HPLC) as ascorbic acid, gallic acid and pyrogallol. The oxidized forms of polyphenols formed coordination with surface of Au NPs which protected their further growth and aggregation. We also propose a plausible mechanism how to tune size and shape of Au NPs by varying the quantity of extracts. Thus obtained Au NPs were stable for more than four months.
本文展示了一种简便、快速、环保的方法，使用Terminalia arjuna 水果提取物的水溶液来合成尺寸可调的金纳米粒子（Au NPs）。通过使用紫外可见分光光度计在 528nm 处的表面等离子体共振（SPR）研究证实了 Au NPs 的形成。通过改变 T. arjuna 水果水提物的用量来研究 Au NPs 的还原时间、尺寸和形态变化。使用紫外可见分光光度计、傅里叶变换红外光谱（FT-IR）、粉末 X 射线衍射（XRD）、透射电子显微镜（TEM）和能谱（EDAX）对合成的 Au NPs 进行了表征。使用高效液相色谱（HPLC）鉴定了负责将 Au(3+)还原为 Au(0)的多酚，鉴定出的多酚为抗坏血酸、没食子酸和焦棓酚。多酚的氧化形式与 Au NPs 的表面形成配位，从而保护其进一步生长和聚集。我们还提出了一种通过改变提取物用量来调节 Au NPs 尺寸和形状的合理机制。因此得到的 Au NPs 在超过四个月的时间里都是稳定的。
