GAOTek offers a various selection of high-quality, affordable and accurate refractometer. A refractometer is an optical instrument that is used to determine the refractive index of a substance, measuring how the light is bent as it moves through the substance.
GAOTek selection of refractometer could suit whatever your need is, providing the best quality and accurate reading wherever it might be.


How the refractometer works is based on the Snell’s Law or the physical principle of light refraction. In which it says that as the light slows down as it passes into a more optically dense media, and speeds up as it passes through a less optically dense media. The change in speed is accompanied by a change in direction and a certain angle. The light does not refract in the second medium at all, but is reflected entirely. The angle at which this occurs is known as the critical angle, at which the refractometer is measured.

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

 There are five types of refractometers. Abbe refractometer, traditional handheld refractometer, Digital refractometer, Automatic refractometer and process refractometer.

·       The Abbe Refractometer is used in measuring liquids. The reference prisms can be selected with high refractive indices. What happens is that, the light from a radiation source is reflected by a mirror and then creates a double prism. The accuracy of the Abbe refractometer is 0.0002

·       The Handheld refractometer is used by beekeepers to determine the water content in the honey, it is also used by wine producers to determine the amount of sugar in the fruit and the grape they are using. It is also used to determine the salt content of water in marine aquaria.

·       The digital refractometer works the same as the hand held refractometer, but offers a more precise reading

·       The Automatic refractometer provides the highest accuracy. This is used more in the laboratory. The modern versions of this equipment has LED lights and interfere with the filter so it make sure that wavelengths are correctly at 589.3nm. This device could be used to measure even a dark, cloudy and opaque samples such as ketchup and other condiments.

·       The Process refractometer allows the refractive index to be continuously analyzed without removing the sample. This is gives a digital readout and output. This particular refractometer does not need and human involvement during the measurement process.

There are two main things that influence the measurements. Influence of wavelength, and influence of temperature.

·       Influence of wave length the index of the refractive of a given sample depends with the wavelength of an object. This are non linear and a characteristic for every material. The decrease of refractive index then results to an increase of 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 be up to 0.00002 in the reflective index, in which the wavelength’s index has to be correctly determined.

·       The influence of temperature.  The temperature of a prism and the sample has to be controlled. This is the reason why sensors are installed in the device. The main job of the sensor is very crucial. The temperature should be precisely measured so it would not cause any detectable change in the refractive index.


GAOTek refractometers offer various features, that are included in the device and are not limited to such features that follow:

·       Operation Temperature: 0- 40C

·       Power supply: 1.5V alkaline battery

·       Operating time: more than 8000 times per battery

·       Operation humidity: lower than 90 percent

·       Operation sea level: lower than 6561.68 feet

·       Other functions: ATC, instant reading,

All GAOTek refractometer are all portable and light- weight, these however does not limit the quality and accuracy of the readings, thus making the product be portable and allows the user to take the high-quality product everywhere without a hassle.


The refractometer is used for seaway ballast water inspections. It can also be used in Veterinary medicine, Gemology also by beekeepers to determine the water content in the honey, it is also used by wine producers to determine the amount of sugar in the fruit and the grape they are using. It is also used to determine the salt content of water in marine aquaria. The automatic refractors are used in food and beverage sectors, and the petroleum industry. The process refractometer can be used in sugar, pulp and paper making process and so as in the refining, chemical sectors and so as in the pharmaceutical industries.

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