a chemical method of quantitative analysis based on the measurement of the intensity of the light scattered by disperse systems. It was originally used in analyzing certain naturally turbid objects, for example, river water. Later, artificial suspensions were used to determine solute concentration. For example, sulfate concentration in water is determined by first using BaCl2 to obtain a BaSO4 suspension; the intensity of light scattering in this medium is next measured with a nephelometer; and, finally, the SO42- ion concentration is found by means of a calibration curve. Nephelometric analysis is currently applied to determine the concentration of petroleum products in water, as well as in the examination of various other products, such as pharmaceuticals and foods. It is a suitable method for determining concentrations of 10-5 to 10-4 percent with an accuracy of approximately ± 5 percent.
Nephelometric analysis is done with special devices called nephelometers, which measure the scattered light through an ocular positioned at a 90° angle to the incident light beam. In addition, certain photoelectric colorimeters, for example, FEK-N-57 and FEK-56–2, are currently being adapted for use as nephelometers.
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IU. A. KLIACHKO