粒径分布分析开发-干法.pdf

Particle Size Distribution Analyzer AN154 Applications Note Dry Method Development Applications Note Applications Note DRY METHOD DEVELOPMENT FOR LASER DIFFRACTION PARTICLE SIZE MEASUREMENTS Developing an appropriate method for measuring particle size distribution of powders dispersed in air using laser diffraction requires a structured approach. The basic goals for developing a dry method include: place a representative sample into the analyzer, disperse the sample using a pressure that breaks up agglomerates but not individual particles, choose appropriate system settings for measurement, and test for reproducibility. Introduction • Accepted standards stress the Developing an appropriate method for importance of sampling. ISO 13320 measuring particle size distribution (3) and USP 429 (4) both using laser diffraction requires a advise that a representative structured approach. Samples sample be prepared using a sample analyzed as a dry powder have a few splitting technique. (5) unique considerations compared to • One of the goals of proper method wet analysis, but the majority of the development is to minimize the content in this document will be total error. If sampling is ignored applicable to all methods. the developer doesn’t know which portion of the total error comes In all cases the basic goals remain the from the sampling. same; decide what the purpose of the measurement is, place a Even once a representative sample has representative sample into the been placed