Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

Abstract

A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi‐automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L‐glutamic acid which crystallises into α (prismatic) or β (needle) form and the non‐polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies. In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non‐spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques.

Physical abrasion of mafic minerals and basalt grains: Application to martian aeolian deposits

“…Lo Guo et al, 2011;Jerolmack et al, 2011). The particle shadows are scanned in 64 directions, providing a precise and detailed analysis of a wide range of particle shapes using CAMSIZER analysis software (e.g., Lo Miller and Henderson, 2010;Patchigolla and Wilkinson, 2010;Jerolmack et al, 2011). Particle shape parameters that are collected in this study include size, roundness, and sphericity (http://www.retsch--technology.com).…”

Prediction of quality attributes of continuously produced granules using complementary pat tools

“…Liew et al [8] captured the particle movement in a fluid bed coater by means of a high-speed video camera. Dynamic digital image processing (Camsizer, Retsch Technology) was used by Patchigolla and Wilkinson [9] for the size and shape monitoring during glutamate-crystallization. Naervanen et al [10] reconstructed threedimensional topographic images by means of red, green and blue led light illumination.…”

Optimising Drug Solubilisation in Amorphous Polymer Dispersions: Rational Selection of Hot-melt Extrusion Processing Parameters

“…Both optical and polarised light microscopes (PLM) are suitable to examine the morphology of embedded crystallites when the matrix is transparent. It is also possible to obtain reliable particle size information using these techniques (45). Figures 9 and 10 illustrate the morphology of FD-EPO extrudates processed using a range of temperatures and screw speeds.…”