The Use of NMR in Quantitative Determination of Oil and Water in Emulsions

Abstract

Nuclear magnetic resonance techniques have been used to determine quantitatively the amount of water and oil in several oil/water emulsions. The technique utilizes the inversion recovery pulse (IR) sequence to produce and measure the amplitude of the spin echoes at non-linearly spaced time intervals. In this study, the temperature and the operating frequency were 24.5°C and 2.5MHz respectively. The quantity of each. component was determined by fitting the data to non-linear models consisting of either one or two exponentials. For n-hexadecane/water and paraffin oil/water, the relaxation behaviour conforms to the two-state non-exchange model. The amount of each constituent could be estimated fairly accurately from the signal amplitudes, Olive oil emulsion, however, appears to be more complex. The difference between signal amplitude ratio and that obtained by weighing is discussed.