Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Anal Bioanal Chem. 2013 Mar;405(7):2279-88. doi: 10.1007/s00216-012-6617-z. Epub 2013 Jan 22.
We report the development of a hyphenated instrument with the capacity to quantitatively characterize aqueous suspended gold nanoparticles (AuNPs) based on a combination of gas-phase size separation, particle counting, and elemental analysis. A customized electrospray-differential mobility analyzer (ES-DMA) was used to achieve real-time upstream size discrimination. A condensation particle counter and inductively coupled plasma mass spectrometer (ICP-MS) were employed as downstream detectors, providing information on number density and elemental composition, respectively, of aerosolized AuNPs versus the upstream size selected by ES-DMA. A gas-exchange device was designed and optimized to improve the conversion of air flow (from the electrospray) to argon flow required to sustain the ICP-MS plasma, the key compatibility issue for instrumental hyphenation. Our work provides the proof of concept and a working prototype for utilizing this construct to successfully measure (1) number- and mass-based distributions; (2) elemental compositions of nanoparticles classified by size, where the size classification and elemental analysis are performed within a single experiment; (3) particle concentrations in both solution (before size discrimination) and aerosol (after size discrimination) phases; and (4) the number of atoms per nanoparticle or the nanoparticle density.
我们开发了一种联用仪器，能够基于气相尺寸分离、颗粒计数和元素分析相结合，定量表征水悬浮金纳米颗粒（AuNPs）。采用定制的电喷雾-差分迁移率分析仪（ES-DMA）实现实时上游尺寸区分。使用凝聚粒子计数器和电感耦合等离子体质谱仪（ICP-MS）作为下游探测器，分别提供气溶胶化 AuNP 的数密度和元素组成信息，这些信息与 ES-DMA 选择的上游尺寸相对应。设计并优化了气体交换装置，以提高将气流（来自电喷雾）转换为维持 ICP-MS 等离子体所需的氩气流的效率，这是仪器联用的关键兼容性问题。我们的工作提供了利用该结构成功测量（1）基于数和质量的分布；（2）按尺寸分类的纳米颗粒的元素组成，其中尺寸分类和元素分析在单个实验中进行；（3）溶液（尺寸区分前）和气溶胶（尺寸区分后）相中颗粒浓度；以及（4）每个纳米颗粒的原子数或纳米颗粒密度的概念验证和工作原型。
