A pragmatic approach to the particle sizing of submicrometre emulsions using a laser nephelometer

The use of a commercial laser nephelometer to measure the mean particle size of submicrometre emulsions is described. The instrument is sufficiently sensitive to measure particles smaller than 600 nm. The method is comparative, and two standard materials of known size that are physically and chemically similar to the test emulsion must be used. The method is rapid and inexpensive, and may be used as a routine, in-house quality control procedure for monitoring emulsion production processes such as homogenization. However, it is only suitable if the average particle size of the system is smaller than 600 nm and, probably, with a relatively narrow size distribution.