Nephelometric Analysis

Nephelometric Analysis 

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 SO₄^2- 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.

REFERENCES

Yoe, J. H. “Fotometricheskii khimicheskii analiz,” vol. 2: Nefelometriia, Moscow, 1936.
Fiziko-khimicheskie metody analiza: Prakticheskoe rukovodstvo, 2nd ed.
Edited by V. B. Aleskovskii and K. B. Iatsimirskii. Leningrad, 1971.
Váńa, J. Analizatory gazov i zhidkostei. Moscow, 1970.
Lur’e, Iu. Iu., and A. I. Rybnikova. Khimicheskii analiz proizvodstvennykh stochnykh vod, 2nd ed. Moscow, 1963.

IU. A. KLIACHKO