Graphite Furnace Atomic Absorption Spectrometry for Sizing Nanoparticles

该项目的目的是开发一种健壮、直接和快速的方法，使用石墨炉原子吸收光谱(GFAAS)来测定金属纳米颗粒的尺寸。新的方法将提供关于多分散悬浮液中纳米颗粒(NP)的尺寸和尺寸分布的可靠结果，特别是对于较低的纳米颗粒尺寸范围。因此，重点是开发一种可重复使用的石墨炉原子吸收法检测粒度和同时测定浓度的方法。在这里，将涉及三个关键方面：1.研究和优化石墨炉中纳米粒子的原子化；2.发展尺寸和浓度关联的校准策略；以及3.基于复杂的真实样品研究该方法的稳健性。对于第一个子目标，重要的是研究纳米颗粒雾化的动力学和热力学作为浓度和尺寸的函数。为此，将在雾化阶段现场记录石墨炉内的实际温度曲线。因此，在其他参数中，可以确定信号的所谓“出现温度”，根据该温度可以计算激活能，并可以推导出雾化的动力学级数。然后，这些理论发现服务于第二个子目标，即开发一种用于粒度测定和金属浓度测定的最佳分析校准策略。此外，还将发展和优化一种多分散悬浮液信号解卷积的数学方法，以获得一种快速测定悬浮液中金属纳米颗粒尺寸分布的方法。在项目的第三部分，将调查更复杂的样品以及可能出现不均匀尺寸分布和异质聚集体的真实样品。确定了该方法的稳健性和可能的局限性。这种成功开发和验证的方法将允许直接、简单和快速地测量真实样品的非常小的纳米颗粒，这是其他方法难以或不可能实现的。此外，与文献中提出的NP分析技术相比，该方法基于不同的物理原理，如单粒子质谱仪或光散射法。因此，该项目的成功还将为纳米颗粒分析的分析质量保证在走向可靠和标准化方法的道路上做出重大贡献。

The aim of the project is the development of a robust, direct and rapid method for the size determination of metal nanoparticles using graphite furnace atomic absorption spectrometry (GFAAS). The new method will provide reliable results on the size and size distribution of nanoparticles (NPs) in polydisperse suspensions, particularly for the lower nanoparticle size range. The focus is therefore on the development of a reproducible method for size detection and simultaneous concentration determination by means of GFAAS. Here, three crucial aspects will be addressed: 1. Investigation and optimization of the atomization of NPs in the graphite furnace; 2. The development of calibration strategies for size and concentration correlation; and 3. Investigation of the robustness of the method on the basis of complex, real samples. For the first sub-goal, it is important to investigate the kinetics and thermodynamics of the atomization of NPs as a function of concentration and size. For this purpose, the actual temperature curve in the graphite furnace will be recorded in-situ during the atomization phase. Thereby, amongst other parameters the so-called "appearance temperature" of the signals can be determined, from which activation energies can be calculated and the kinetic order of the atomization can be derived. These theoretical findings then serve the second sub-goal, the development of an optimal analytical calibration strategy for both particle size determination and metal concentration. Furthermore, a mathematical method for the deconvolution of signals from polydisperse suspensions will be developed and optimized in order to obtain a rapid method for the size distribution of metal nanoparticles in suspensions. In the third part of the project, more complex samples as well as real samples are to be investigated in which both a heterogeneous size distribution and heteroaggregates may occur. The robustness and possibly limits of the method are determined. The successfully developed and validated method will allow a direct, simple and fast sizing of even very small nanoparticles of real samples, which is difficult or impossible to access with other methods. In addition, the method is based on a different physical principle compared to the techniques of NP analysis proposed in the literature, such as single-particle mass spectrometry or light scattering methods. Thus, the successful project will also make a significant contribution to the analytical quality assurance of nanoparticle analysis on the way to reliable and standardized methods.