A refractometer is a laboratory or field device for the measurement of an index of refraction (refractometry). The refractive index of a certain sample varies for nearly all materials for different wavelengths. This dispersion relation is characteristic of every material. The temperature has a very important influence on the refractive index measurement. Therefore, the temperature of the prism & the temperature of the sample have to be controlled with high precision.
Uses of Refractometer:
-Alcohol industry: Measuring specific gravity before the fermentation process to determine the amount of sugar.
-Veterinary-Measurement of proteins in the blood, measurement of urine weight
-Human medicine-Measuring urine weight
-Beverages-Measuring the sugar in aqueous solutions
-Gemology-Identifying and characterizing the quality of gems
-Automotive Industry-Measuring the Freezing Point of Battery Cooling Fluids
-Aquarium- Measuring the salinity level of water
What to consider before purchasing a Refractometer
-What is my rationale for buying a refractometer?
-What kinds of materials will I be analyzing? Are my samples homogeneous, or do they contain undissolved elements?
-How sensitive must my refractometer be?
-Which regulatory standards does my workplace adhere to?
-Will my refractometer be used in harsh environmental conditions?
-Will the applications I have in mind place restrictions on the size or shape of my system?
Automatic Refractometer
Automatic refractometers automatically measure the refractive index of a sample. The automatic measurement of the refractive index of the sample is based on the determination of the critical angle of total reflection.An LED light source is imaged under a wide range of angles onto a prism surface which is in contact with a sample. Depending on the difference in the refractive index between prism material and sample the light is partly transmitted or totally reflected. The critical angle of total reflection is determined by measuring the reflected light intensity as a function of the incident angle
This method of detecting the angle of total reflection is independent on the sample properties. It is even possible to measure the refractive index of optically dense strongly absorbing samples or samples containing air bubbles or solid particles . Furthermore, only a few microliters are required and the sample can be recovered. This determination of the refraction angle is independent of vibrations and other environmental disturbances.
Watch: How to use a refractometer https://www.youtube.com/watch?v=Qd9uJ9JitJw