Refractometry is a method for measuring refractive index, which is one of the characteristics of a substance. Тhe refractive index makes it possible to determine other characteristics that have great practical application - the density of the medium, the content of impurities, the concentration of the solution and the quality. The method is based on the phenomenon of light refraction at the boundary of two media, in which light propagates at different rates. The principle of the device is based on the measurement of the critical angle (the angle of total internal reflection) and the calculation of the refractive index, using the Snelius law.
This article describes the physical basis of refractometry, the principle of measuring of the refractometer and its structure. Analysis of the dependence of the refractive index on temperature and wavelength is carried out. The measuring of the refractive index is a simple and useful method to determine the concentration of substances and their characteristics. It is often used in research and industrial laboratories, both for quality control and for product development. It is also used for the study of pharmaceuticals, food analysis (including quality control of honey), assessment of perfume and fragrances, as well as online monitoring of food, beverages and medicines.