Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
National Nanotechnology Center, National Science and Technology Development Agency, 111 Phahonyothin Rd., Klongluang, Pathumthani, 12120, Thailand.
Talanta. 2022 Jan 1;236:122871. doi: 10.1016/j.talanta.2021.122871. Epub 2021 Sep 11.
Bimetallic nanoparticles (NPs), including core-shell structure and bimetallic alloy nanoparticles, were synthesized and characterized using flow field-flow fractionation (FlFFF), single particle inductively coupled plasma mass spectrometry (SP-ICP-MS), and transmission electron microscope (TEM) with energy-dispersive x-ray spectroscopy (EDS). For the core-shell particles, a nominal 80 nm commercial core-shell AuAg bimetallic nanoparticle was used to examine the applicability of SP-ICP-MS to determine the core size of Au and shell thickness of Ag. Then, the method was applied to estimate the core size of Au and shell thickness of Ag for the laboratory synthesized particles. The results were compared with those obtained from TEM-EDS. For the alloy nanoparticles, two synthesis protocols, based on the galvanic replacement of Ag seed particles with Au, were used. One was to prepare a hollow AgAu particle by varying the volume of dissolved Au in basic solution (K-gold) to etch some parts of AgNPs to dissolved ionic silver with the formation of AuNPs covering the remaining AgNPs, producing a hole inside the core nanoparticles. Another protocol was to prepare AgAu alloy nanoparticles. SP-ICP-MS was used in combination with FlFFF to provide information on the changes of particle size with varying volume of K-gold reagent. Hydrodynamic diameter increased with increasing K-gold, as observed by FlFFF. With SP-ICP-MS without prior FlFFF, bimodal distributions were observed in the size distribution of Au and Ag. With prior FlFFF, monomodal distributions were observed by SP-ICP-MS, which allow the use of particle concentration and size to estimate the mass concentration of elements on the fractionated bimetallic nanoparticles. This study illustrates the potential use of SP-ICP-MS for gaining information about particle transformation during the synthesis of bimetallic nanoparticles.
双金属纳米粒子（NPs），包括核壳结构和双金属合金纳米粒子，使用流场流分离（FlFFF）、单颗粒电感耦合等离子体质谱（SP-ICP-MS）和透射电子显微镜（TEM）与能量色散 X 射线光谱（EDS）进行合成和表征。对于核壳颗粒，使用标称 80nm 的商业核壳 AuAg 双金属纳米颗粒来检验 SP-ICP-MS 确定 Au 核大小和 Ag 壳厚度的适用性。然后，将该方法应用于估计实验室合成颗粒的 Au 核大小和 Ag 壳厚度。结果与 TEM-EDS 获得的结果进行了比较。对于合金纳米粒子，使用了两种基于 Ag 种子颗粒与 Au 的电替换的合成方案。一种是通过改变溶解在碱性溶液（K-gold）中的 Au 体积来制备空心 AgAu 颗粒，以蚀刻部分 AgNPs 至溶解的银离子，形成覆盖剩余 AgNPs 的 AuNPs，从而在核纳米颗粒内部形成一个孔。另一种方案是制备 AgAu 合金纳米粒子。将 SP-ICP-MS 与 FlFFF 结合使用，提供了随 K-gold 试剂体积变化的粒径变化信息。FlFFF 观察到，随着 K-gold 的增加，流体动力学直径增加。未经 FlFFF 预处理的 SP-ICP-MS 观察到 Au 和 Ag 的粒径分布呈双峰分布。经 FlFFF 预处理的 SP-ICP-MS 观察到单峰分布，允许使用粒子浓度和尺寸来估计分馏双金属纳米粒子上元素的质量浓度。本研究说明了 SP-ICP-MS 在获得双金属纳米粒子合成过程中粒子转化信息方面的潜在用途。
