A new coupling setup of DMA, CPC and sp-ICP-MS with increased versatility

Accurate mass measurements of aerosol nanoparticles are inherently challenging. Beyond pure mass determination, such as can be realized using centrifugal particle mass analysis, aerosol mass spectrometry also enables material-specific analysis. In this work, the hyphenation of an inductively coupled plasma mass spectrometer working in single particle mode (sp-ICP-MS) with a scanning mobility particle sizer (SMPS) is presented. The coupling of the instruments is described, with special attention to the position of the gas exchange device, which allows flexible interconnection of DMA and ICP-MS while maintaining the full classification range of the DMA. The mass calibration of the ICP-MS signal and the limits in terms of particle concentration were studied on spherical gold nanoparticles. As an application example, the structure of gold nanoparticle agglomerates was characterized as a function of a preceding temperature treatment. The fractal dimension and the effective density of the agglomerates is directly determined after sintering at various temperatures. In addition, a new approach to derive the primary particle diameter from the measurement of agglomerate mass is outlined. Finally, the possibility of analyzing the particle charge is shown in perspective.

Automated summary

This study presents a method of combining sp-ICP-MS and SMPS for accurate mass measurements and material-specific analysis of aerosol nanoparticles. The feasibility of this method is demonstrated through testing and researching gold nanoparticles, and measurement results of the structure of gold nanoparticle agglomerates and the primary particle diameter are provided.