Comparative and inter-conversion analysis of dry and wet methods of particle size distribution using a test case of batch sedimentation

The present study addresses the challenges associated with the comparison of particle size distributions (PSDs) generated by using different instruments and methods. The various experimental methods yield different types of PSD, which can appear dissimilar. These dissimilarities are described in the current study, and the possibility of inter-conversion between the different PSDs is examined. PSDs are generated for a set of three powders obtained from batch sedimentation experiments. Two different experimental methods are used for the PSD generation; a dry method (using microscopy, yielding a number frequency PSD) and a wet method (using laser-scattering, yielding a volume frequency PSD). The relative merits of both methods and the strengths of both types of PSD are assessed through statistical comparisons. It is found that the two types of PSD contain similar information and can be inter-converted, subject to limitations of the experimental procedure and particle shape which are addressed in the current investigation. Graphical abstract