Direct Determination of Lipoprotein Particle Sizes and Concentrations by Ion Mobility Analysis

centrations of lipoprotein particles and their distribu-tions in particle subpopulations are not standardized. We describe here and validate a new gas-phase differ-ential electrophoretic macromolecular mobility-based method (ion mobility, or IM) for direct quantification of lipoprotein particles, from small, dense HDL to large, buoyant, very-low-density lipoprotein (VLDL). METHODS: After an ultracentrifugation step to remove albumin, we determined the size and concentrations of lipoprotein particles in serum samples using IM. Scan time is 2 min and covers a particle range of 17.2–540.0 Å. After scanning, data are pooled by totaling the par-ticle number across a predetermined size range that corresponds to particular lipoprotein subclasses. IM results were correlated with those of standard method