New method for density determination of nanoparticles using a CPS disc centrifuge™

A model has been developed for the determination of the correct absolute size of nanoparticles using a disc centrifuge; the method does not require externally measured or literature derived particle densities. The principle of this method is the altered settling velocity of particles in fluids with different viscosities and/or densities, with the use of a linear regression analysis for the calculation of particle densities. This allows a fast particle density determination with at least two measurements using a disc centrifuge and a small subset of easily measurable parameters. Furthermore, correctness of the model is evaluated using viruses and nonbiological particles of known densities.

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► Size determination by disc centrifugation is a common method.
► Buoyant density is needed for correct size determination.
► A model for the density determination using the disc centrifuge was derived.
► Model was validated with several particles, including anorganic and virus particles.