DETERMINATION OF WATER DROPLET SIZE DISTRIBUTIONS BY LOW-RESOLUTION PFG-NMR

The aim of this work is to show that a low resolution NMR spectrometer in combination with a pulsed field gradient unit can be used for the determination of the water droplet size distributions of water-in-oil emulsions. To improve the treatment of NMR measurements, we added an unrestricted diffusion component to the restricted one used up to now. The purpose of this second term is either (i) to improve the fitting of the experimental values to take into account that the distribution of the droplet sizes is not perfectly lognormal, or (ii) to show a significant unrestricted diffusion component due to poor emulsification of the sample. The NMR results are compared with those of laser diffraction. These results are the first step in a study of ''solid'' water-in-oil emulsions such as butter or margarine. (C) 1994 Academic Press, Inc.