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Commercial reference shape standards use in the study of particle shape effect on laser diffraction particle size
Richard N Kelly1, Jacqueline Kazanjian
1Johnson & Johnson Pharmaceutical Research & Development, LLC, Room P-1029 McKean & Welsh Roads, Spring House, PA 19477-0776, USA. RKelly@prdus.jnj.com
AAPS Pharmscitech
|June 27, 2006
Summary
Particle shape significantly impacts laser diffraction particle size analysis (psa). This study reveals that particle shape effects can lead to inaccurate results, questioning standard interpretation models for nonspherical particles.
Area of Science:
- Analytical Chemistry
- Materials Science
- Physics
Background:
- Laser diffraction (LD) is a common method for particle size analysis (psa).
- Accurate psa of nonspherical particles using LD is challenging.
- Standard models often assume spherical particles or random orientation.
Purpose of the Study:
- To investigate the effect of particle shape on LD psa.
- To evaluate how experimental variables modify shape effects in LD psa.
- To test the validity of current LD psa interpretation models for nonspherical particles.
Main Methods:
- Utilized monosized fiber-analog shape standards (AEA 1001-1003).
- Performed LD psa using systems from Beckman Coulter, Horiba, and Malvern Instruments.
- Varied flow speed, refractive index, and sample cell type.
Main Results:
- Particle size distributions showed spreads related to particle dimensions.
- Volume probability plots often exhibited apparent bimodal distributions.
- Experimental results verified theoretical predictions for elliptical particles.
Conclusions:
- Particle shape significantly influences LD psa outcomes.
- Apparent bimodality in volume plots is linked to particle orientation.
- Current models (equivalent spherical volume diameter, random orientation) are questioned for nonspherical particles.