
Photo of a Handheld Refractometer used to measure sugar content (Brix level) of fruits. The image includes a view through the eyepice of the instrument, a small drop of orange juice was put over the measuring prism to take the picture.
A 'refractometer' is an optical instrument that is used to determine the
refractive index of a substance. This often refers to some physical property of a substance that is directly related to its refractive index. Certain types of refractometers can be used for measuring
gases,
liquids such as
oils or
water-based, and even transparent or translucent solids such as
gemstones.
A refractometer can be used to determine the identity of an unknown
substance based on its
refractive index, to assess the purity of a particular substance, or to determine the concentration of one substance dissolved in another. Most commonly, refractometers are used for measuring fluid concentrations such as the sugar content (
Brix level, for example in
carbonated beverages,
fruits,
juices, and or
vegetables, etc), blood protein concentration,
salinity and
specific gravity of urine. Refractometers are also used for measuring fluid concentrations for commercial liquids such as
antifreeze,
cutting fluid, and industrial fluids.
Types of refractometers
There are four main types of refractometers:
traditional handheld refractometers,
digital handheld refractometers, laboratory or
Abbe refractometers, and
inline process refractometers.
There is also the
Rayleigh Refractometer used (typically) for measuring the refractive indices of gases.
In
veterinary medicine, a refractometer is used to measure the total
plasma protein in a blood sample.
External links
★
Rayleigh Refractometer: Operational Principles