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 a (prismatic) or ß (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, D 90, 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 nonspherical 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. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA,Weinheim.
|Number of pages||8|
|Journal||Particle and Particle Systems Characterization|
|Publication status||Published - Jan 2010|
- Crystal size and shape
- Dynamic image analysis
- Microscopic image analysis
- Statistical analysis