ANALYTICAL APPLICATIONS OF PHOTON-CORRELATION SPECTROSCOPY FOR SIZE DISTRIBUTION MEASUREMENTS OF NATURAL COLLOIDAL SUSPENSIONS - CAPABILITIES AND LIMITATIONS

Particles are ubiquitous in all natural systems and play an important role in the control and fate of nutrients and pollutants. Currently, o nly limited information is available concerning particle number and si ze distributions, owing to the problems involved in their experimental determination. In the present paper, limitations and optimal conditio ns for particle size determinations of environmental samples using pho ton correlation spectroscopy are studied. The detection limit, the eff ects of polydispersity of the sample and the refractive index value ar e discussed based on results obtained with synthetic colloids. The pho ton correlation spectroscopic determination of particle size distribut ions in real aquatic systems is also presented in the second part of t he paper.