Graphite Furnace Atomic Absorption Spectrometry for Sizing Nanoparticles

该项目的目的是开发一种可靠、直接和快速的方法，用于使用石墨炉原子吸收光谱法（GFAAS）测定金属纳米颗粒的尺寸。新方法将为多分散悬浮液中纳米颗粒的尺寸和尺寸分布提供可靠的结果，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的方法，用于通过GFAAS进行粒度检测和同时测定浓度。在这里，将讨论三个关键方面：1。石墨炉NPs雾化的研究与优化2. 粒径与浓度相关性校正策略的发展和3。在复杂、真实样本的基础上对该方法的鲁棒性进行了研究。对于第一个子目标，重要的是研究NPs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，除其他参数外，可以确定信号的所谓“外观温度”，由此可以计算活化能并推导出原子化的动力学顺序。然后，这些理论发现服务于第二个子目标，即为粒径测定和金属浓度开发最佳分析校准策略。此外，我们还将开发和优化多分散悬浮液信号反褶积的数学方法，以获得金属纳米颗粒在悬浮液中尺寸分布的快速方法。在该项目的第三部分，将研究更复杂的样本以及真实样本，其中可能出现异质尺寸分布和异质聚集体。确定了该方法的鲁棒性和可能存在的局限性。成功开发和验证的方法将允许直接，简单和快速地确定真实样品的非常小的纳米颗粒的尺寸，这是用其他方法很难或不可能获得的。此外，与文献中提出的NP分析技术（如单粒子质谱法或光散射法）相比，该方法基于不同的物理原理。因此，该项目的成功也将为纳米颗粒分析的分析质量保证做出重大贡献，从而实现可靠和标准化的方法。

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.