Refractometers are used to measure the refractive index of a liquid or solid, which provides information about its composition and purity in applications as diverse as measuring sugar, honey, salt, wine, beer, alcohol, coffee, urine, batteries, etc. Refractometry is a quantitative, non-destructive measuring technique based on optical principles. The refractive index is a specific value for a material and it depends on the temperature and the wavelength (? = color) of the light. A refractometer can therefore be used to determine the concentration of a substance if the temperature and wavelength are known.
Digital laboratory refractometers