AN IMPROVED PROCEDURE FOR ESTIMATING SIZE DISTRIBUTION PARAMETERS OF SPHERICAL AND NONSPHERICAL PARTICLES FROM THEIR PLANAR CROSS-SECTIONS

Direct determination of size distributions or average size parameters of particles in disperse systems on the basis of thin planar sections or cleavages, as e.g. from TEM micrographs of thin-sectioned or freeze -fractured specimens, requires adequate mathematical procedures for co nverting the apparent, i.e, two-dimensional, to the true, i.e. three-d imensional, data. In case only certain average size parameters are nee ded to characterize the disperse phase it is relevant to limit the amo unt of measurements, especially if automated image analysis is not app licable or available. This paper describes a procedure to simplify the efforts required for measurement and calculation. Four examples of di sperse systems are given, i.e. (I) an O/W-type emulsion, (II) a spray- dried O/W emulsion (topping powder), (III) phospholipid liposomes and (IV) colloidal protein aggregates in milk.