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What is a Refractometer?

Refractometers is a instrument used for measuring concentrations of aqueous solutions, also known as "brix meter". 

Standard refractometers measure the extent of light refraction (as part of a refractive index "nD") of transparent substances in either a liquid or solid-state; this is then used in order to identify a liquid sample, analyze the sample's purity, and determine the amount or concentration of dissolved substances within the sample. As light passes through the liquid from the air it will slow down and create a ‘bending’ illusion, the severity of the ‘bend’ will depend on the amount of substance dissolved in the liquid.

For example, the amount of sugar in a glass of water. 

Using these values, you can determine the concentrations of solutions.

ATAGO USA we provide large selections of bentop, handheld versions of Abbe, analog, and digital refractometers that are suitable for various industires! 

Types of refractometer include:

  • Handheld Analog Refractometers are held up to a light source, such as the sun, so that light is directed through the sample, a prism and lenses onto a measurement scale. The angle at which light is totally internally reflected determines the position of a shadow line on the scale, which can then be viewed through an eyepiece.
  • Handheld Digital Refractometers work in essentially the same way as the traditional analog refractometers, with a shadow line indicating the angle at which total internal reflection occurs.However with digital refactometer itslef includs an LED light source. This can improve accuracy by controlling the wavelength more accurately. The eyepiece and glass scale is also replaced by optical glass to prevent scratching, enabling the shadow line to be digitally detected and the relevant measurement result displayed on a screen.
  • Abbe Refractometers are bench-top instruments designed for more accurate measurement on refractive index. They therefore typically need some temperature control of the sample. Usually used in labratory. 
  • In-line Refractometers continuously measure the refractive index of a fluid as it flows through the sensor. Monitoring and managing whether the processing, blending, and concentration changes are conducted as planned allows for immediate detection of any manufacturing issues and prevents out-of-spec products, thereby resulting in accurate, reliable quality control for the utmost "safety.
  • Digital Benchtop Refractometers are designed to be highly accurate and provide reliable measurements while facilitating a simple measurement method for the operator.


Application of Refractometers

Use 1  Measuring Refractive Index 

Refractive index is one of the physical constants of a substance, and each substance has its own refractive index.
Refractometers are used to measure pharmaceuticals, flavor and fragrance ingredients, chemicals, glass, plastics, etc. for material identification and quality control purpose.


Use 2  Measuring Sugar Concentration

Refractometers can be used to measure Brix values of sugar-rich samples, such as fruit juice, syrup, jam, and honey.
The measurement value correlates to the sugar concentration of the sample measured. As described in the "About the Brix (%) Scale" on the following page, Brix is the number of grams of cane sugar dissolved in 100 grams of water.
The conversion factor between refractive index and Brix values is determined by the lnternational Commission for Uniform Methods of Sugar Analysis (ICUMSA) .

Use 3  Measuring Concentration of Food Items

Sauces, paste, juice, and other liquid food items have multiple ingredients, such as sugar and salt. Values measured by refractometers are proportional to the total concentration percentage of all dissolved substances.
In this case, the Brix value is interpreted as the concentration of the sample, rather than just the sugar content.

Use 4  Measuring Concentration of Other Liquids

Refractometers can be used to determine the concentration of a wide range of liquids including metal-working fluids, pharmaceuticals, cleaning solutions, coolants, and rust inhibitors.
A correlation between the concentration of a substance dissolved in water and its Brix value may be observed. By plotting the values of the concentrations and corresponding Brix readings, a user scale can be created.
On the other hand, the Brix scale as is, is widely used as a relative measure of dissolved solids.