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GAOTek provides a wide range of high quality, feature-rich and precise refractometers for sale to the United States, Canada and globally. This device is an optical instrument for examining the refractive index of a substance, i.e. for measuring how light bends as it moves through a substance. These devices can provide accurate reading for any substance in any environment.
GAOTek offers refractometers designed for a wide range of applications, whether it be for laboratory use, production line, or more.


A refractometer works on the principle of Snell’s Law or the physical principle of light refraction that states that light slows down as it passes into an optically dense medium, and speeds up as it passes through a less optically dense medium. The change in speed from a dense medium to a lighter medium, and vice versa, is associated by a change in direction and angle. The angle at which this occurs is known as critical angle. A refractometer measures refraction at this angle.

Snell’s law provides a formula that can be used to figure out the direction of light through refractive media with varying indices of refraction. As light passes through, the border between media depends upon the relative refractive indices of two medias. There are two possibilities, the light may be refracted to a lesser angle or a greater angle. This is then measured in consideration with the normal line which is perpendicular to its boundary.

Mainly there are five types of refractometers – abbe refractometers, traditional handheld refractometer, digital refractometer, automatic refractometer, and process refractometer.

Abbe refractometer is utilized for measuring liquids. The accuracy of Reference prisms can be selected with high refractive indices. Light from a radiation source is reflected by a mirror and creates a double prism. The accuracy of Abbe refractometer is 0.0002.

Beekeepers use handheld refractometer to determine water content in honey. Wine producers also use it to determine the amount of sugar content in a fruit or specifically in the grape used. It is also used to determine salt content of water in marine aquaria.

Digital refractometers work same as hand held refractometer, but it offers more precise and accurate reading.

Automatic refractometers are highly accurate devices and they are mostly used in laboratories. The latest versions of these devices are equipped with LED lights and interface with filter to ensure the correct wavelength at 589.3nm. It can also be used to evaluate dark, cloudy and opaque samples like ketchup and other condiments.

Process refractometer allows the refractive index to be continuously analyzed without having to remove the sample. This gives a digital reading and output. This refractometer does not need any human intervention during the measurement process.

The two main factors that influence measurements – wavelength and temperature.

Influence of wavelength – Refractive index of a given sample depends on the wavelength of an object and it is non-linear and unique for every material. The decrease in refractive index results in an increase in wavelength.

Refractive index of a given sample depends on the wavelength of an object. This is non-linear and unique for every material. The decrease in refractive index results in an increase in wavelength. In an infrared wavelength, the absorption maxima and fluctuation on the refractive index appear. For a high-quality measurement to be made, the accuracy sound need to be 0.00002 in the reflective index so that wavelength index can be correctly determined.

Influence of temperature - The temperature of prism and sample must be controlled. This is the main job of a sensor. Temperature should be accurately measured so it does not cause any detectable change in refractive index.


GAOTek’s refractometers provides wide range of features, some of those are listed below:

  • Operating Temperature:0- 40C
  • Power supply:5V alkaline batter
  • Operating time: more than 8000 times per battery
  • Operating humidity: lower than 90 percent
  • Operating sea level: lower than 6561.68 feet
  • Other functions: ATC, instant reading.

All the GAOTek’s refractometers are easy to carry and light-weight devices. However, this does not affect their quality and accuracy. Portability enables the user to take these high-quality products anywhere without any issues.


A refractometer is used for seaway ballast inspections. Moreover, it is also used in veterinary medicine, gemology, and by beekeepers to determine the water content in honey. Wine producers also uses it to measure the amount of sugar in a fruit used. It is also used to determine the salt content of water in marine aquaria. Automatic refractors are mostly used in food and beverage sector, and in petroleum industry. In addition, a process refractometer can be used in sugar, pulp and paper making process and in refining, chemical, and pharmaceutical industries.

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