Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Accurate Nanoparticle Size Determination using Electrical Mobility Measurements in the Step and Scan Modes



Kaleb Duelge, George Mulholland, Vincent A. Hackley, Michael Zachariah


A critical and extensive comparison was made between differential mobility analysis (DMA) measurements of the mean diameter of monodisperse gold nanoparticles (AuNP), based on step-voltage mode and the more commonly used scan-voltage mode (commercially known as scanning mobility particle sizer, SMPS). Under specific conditions, the difference between the two modes of operation were less than the combined uncertainty for the step-voltage mode. Additionally, a comparison was made between two different calibration methods for DMA: the use of a certified nanoparticle size standard (artifact) versus a direct measurement of the sheath flow rate. Important variables and limitations for accurate measurements by the scan-voltage method were identified and evaluated. The mean size shifts to smaller diameters as the scan time is reduced and the scan mode is unable to measure sufficient points across the peak of very narrow size distributions, leading to systematic errors. Conversely, the speed of the scan-voltage mode can be an advantage and allow for a faster data collection rate for distributions that are changing rapidly with time. A methodology was presented for the use of these and other monodisperse calibration particles for accurately calibrating SMPS instruments for the measurement of the mobility diameter distribution.
Aerosol Science and Technology


differential mobility, particle size, aerosol, nanoparticle, gold, calibration, metrology, scanning mobility, step mode


Duelge, K. , Mulholland, G. , Hackley, V. and Zachariah, M. (2022), Accurate Nanoparticle Size Determination using Electrical Mobility Measurements in the Step and Scan Modes, Aerosol Science and Technology, [online],, (Accessed June 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created October 12, 2022, Updated December 14, 2022