在高分子或界面活性劑溶液中，化學方法製備金銀核殼型奈米粒子常以金奈米粒子為晶種。相較於陽離子型界面活性劑，除了光化學法與物理方法外，陰離子型界面活性劑(SDS)較少於室溫條件下被使用。因此，本篇探討在SDS溶液中，金銀核殼型奈米粒子的成長機制，藉由維生素C還原硝酸銀，使銀覆蓋至金奈粒子表面，並藉由EDTA被作為添加劑與嵌合劑，避免銀離子與金奈米粒子表面的SDS形成很強的作用力，進而改善生成的金銀奈米粒子的聚集現象，由實驗結果顯示，在溶液中大部份的銀離子會先與EDTA形成錯合物，而少部分銀離子吸附到金奈米粒子表面的SDS上，且快速地被還原，而與SDS和EDTA結合的銀離子，接著還原在先前所成長的銀殼上，若於金奈米粒子溶液中添加其他金屬離子(Cu2+、Zn2+)，由實驗結果發現，金奈米粒子對銀離子具有較高的選擇性。 Gold nanoparticles (NPs) were usually used as the seeds in the preparation of Au-Ag NPs in the solutions of polymer and surfactants by wet chemical methods. In contrast to cationic surfactants, anionic sodium dodecyl sulfate (SDS) has been seldom used at room temperature in additional to photochemical and physical methods. Mechanism of the growth of the silver shell on gold NPs was investigated in SDS solutions. Silver deposition on Au NPs was achieved by reducing silver nitrate with ascorbic acid. EDTA is used as both an additive and the chelating agent to prevent the strong interaction of silver ions with the SDS on the AuNPs surface, and it could improve the formation of Au-Ag NPs aggregation. The experimental results suggest that most of the silver ions form chelate with EDTA in the solution at first. But, the part of the silver ions is adsorbed on SDS on the surface of gold NPs in which silver reduction quickly takes place in the reaction solution. The other complex forms of the silver with SDS and EDTA are subsequently reduced on the pre-from silver shell of the resulting Au-Ag NPs. When added the other metal ions (Cu2+, Zn2+) in the solution of AuNPs, the experimental results showed that silver ions with high selectivity.