When multiple instruments are used in tandem it is possible to obtain more complete information on particle transport and physicochemical properties than can be obtained with a single instrument. This article discusses tandem measurements in which submicrometer particles classified according to electrical mobility are then characterized with one or more additional methods. Measurement combinations that are summarized here include mobility plus mass, aerodynamic (or vacuum aerodynamic) diameter, integrated or multiangle light scattering, composition by single particle mass spectrometry, electron microscopy, and so on. Such measurements enable intercomparisons of different measures of size including mobility diameter, optical size, aerodynamic diameter, volume (for agglomerates and nanowires), length (for nanowires), and mass, even for particles that are morphologically and chemically complex. In addition, the article summarizes the use of tandem techniques to measure various transport properties (e.g., dynamic shape factor, sedimentation speed, diffusion coefficient) and physicochemical properties (e.g., mixing state, shape, fractal dimension, density, vapor pressure, equilibrium water content, composition). In addition to providing an overview of such tandem measurements we describe previously unreported results from several novel tandem measurement methods.
Bibliographical noteFunding Information:
The research described in this article was supported by NSF Grants ATM 0096555 and BES-0646507 to the University of Minnesota. DDD is funded by the Graduate Research for the Environment Fellowship, Global Change Education Program, Department of Energy. The final data analysis was partially supported by Eco Science-Technology Advancement Research Project by MOE, Korea Research Foundation Grant (KRF-2007-331-D00222), and Korea Science and Engineering Foundation (KOSEF) grant (No. R01-2007-000-10391-0).