ELECTRICAL SIZING OF PARTICLES IN SUSPENSIONS .2. EXPERIMENTS WITH RIGID SPHERES

Experimental verification is provided for the theoretical expressions (see preceding article, I. Theory) describing the electrical processes that take place during the passage of an aqueous suspension of rigid, nonconducting spheres (ragweed pollen) through an orifice across which there exists an electrical field, for a large range of orifice dimensions; the instrumentation developed is considered in some detail. The effective length of an orifice as deduced from conductivity measurements is shown to be essentially the same as that predicted theoretically. Absolute volume distributions are presented of a suspension of polystyrene latex spheres as determined electrically (mean 11.17 μ3, c. v. 4.2%) and with an electron microscope (mean 11.01 μ3, c. v. 4.1%). Conflicting experimental results reported in the literature are discussed. © 1969, The Biophysical Society. All rights reserved.