Differential centrifugal sedimentation is a powerful tool for nanoparticle size analysis. This method allows for the sedimentation of nanoparticles within a reasonable time frame while achieving extremely high resolution. This capability is remarkable, especially considering that nanoparticles tend to settle very slowly.
The sedimentation process relies on the principle that larger and heavier particles settle faster than smaller and lighter ones. By knowing the particle density and the centrifugal force, we can calculate the Stokes equal sphere diameter. However, since nanoparticles are very light and sediment slowly, we need to accelerate this process significantly.
We achieve this acceleration by using a small disc centrifuge that can rotate at speeds up to 24,000 rpm. This high rotational speed enables the centrifuge to cover a wide dynamic range of particle sizes, from 2 nanometers to 80 micrometers. However, the primary focus remains on the nanoparticle size range.
Despite the broad dynamic particle size range, differential centrifugal sedimentation still provides high-resolution particle size distributions. This capability makes it an invaluable method for analyzing nanoparticles in various applications, ensuring accurate characterization and compliance with regulatory standards.
Advanced Nanoparticle Sizing with Differential Centrifugal Sedimentation
In our laboratory, we utilize the latest CPS DC24000 UHR centrifuge from CPS Instruments. Acquired in 2020, this model is currently the top choice on the market, providing very high nanoparticle size resolution. Traditionally, differential sedimentation analysis could not analyze particles with a lower density than water in a water medium. However, our instrument offers the option to analyze nanoparticles with a density lower than water.
For these materials, we employ the inverse sedimentation principle. In this process, nanoparticles float to the surface instead of settling to the bottom. Therefore, we introduce the particles at the bottom of the liquid phase, forcing them to move upwards. This innovative approach allows us to effectively analyze low-density nanoparticles.
Differential centrifugal sedimentation is one of several nanoparticle sizing techniques available. It serves as a confirmatory method for nanoparticle analysis and nanomaterial classification. While BET surface area analysis is typically used as a screening method for detecting nanoparticles, our differential centrifugal sedimentation analysis complements this process. Additionally, electron microscopy is also considered a confirmatory technique for identifying nanoparticles in solid materials.
By leveraging these advanced techniques, we ensure precise characterization of nanoparticles, supporting regulatory compliance and enhancing product development in various applications.
