Application of refractometers and refractometry in chemistry

Refractometry is a method of testing physicochemical properties of a substance by measuring its refractive index. Refractive index is measured using device called refractometer. Refractive index can be used to asses substance purity or concentration, or to help identify the substance. While refractometry is most often used to measure refractive index of solutions, it is also very important method for testing solids and gases.

Refractive index is always a function of temperature and wavelength, so they have to be precisely controlled during the test. There are many types of refractometers, the most popular model used in labs being Abbé refractometer.

Apart from labs there are many uses of refractometry in many trades - for example they can be used to asses ripeness of grapes before harvesting them, to check alcohol content during fermentation, to check honey quality, antifreeze concentration in cars, electrolyte concentration in car batteries and so on.