Refraction is the change in the velocity of a light wave that hits a surface as it passes from one medium to another with a different refractive index. The refractive index is the ratio between the speed of light in vacuum and the speed of light in another substance, is a physical property characteristic of each species (solid, liquid or gaseous) that is characterized by the propagation of light in a given medium. This parameter of analysis is a good approximation for media where losses by absorption or other phenomena are negligible.

The measuring instrument associated with this parameter is called a refractometer. Its operation is based on measuring the amount of curvature of light passing through the sample. The formula behind the phenomenon is Snell’s law, which is often used to describe the relationship between angles of incidence and light.

The Refractometer

A refractometer has as its main function to contribute to the process of identifying substances and to check their purity. It is usually composed of a light source, a prismatic system that includes a container where the sample is deposited, and a detector to quantify the intensity of the light beam.

The first commercially available refractometer was the Abe. This device was designed by E. Abbe in 1869 to measure the refractive index of sugary liquids. The principle of the equipment remains the same today, the shapes, sizes, specifications and technology depends solely on the manufacturer and cost associated with the requirements of the user.  Over time the accuracy of measurements in these instruments has increased, as modifications such as prism coating, closed-circuit control systems, light filter, and accessories adapted to experimental methodologies have been incorporated. Consequently, by 1930 the hand-held or portable refractometer was presented by the English company Bellingham + Stanley proposed to determine sucrose in cane juice.

The importance of the refractometer

It is a non-invasive measuring instrument, i.e. it does not affect in any way the nature of the sample and only small amounts are used for the assessment. It is distinguished from other equipment by its practicality, as it does not require a complex preparation of the samples to be evaluated. In addition, it offers a variety of applications in areas such as scientific research for the validation of new products and quality control in the industry.

Advantages of using the refractometer

The refractometer is a laboratory and field equipment characterized by its low cost, among its functions it is possible to highlight:

• Verification of purity in oils, wine, alcohol.
• Establish shelf life of food products.
• Measuring the quality of a given product.
• Standardization of processes.
• Monitoring process variables.
• Pharmaceutical composition and drug diversion.
• Control and quantification of critical points for obtaining international certifications.
• For quality control of products and processes.
• For measurement of ripening status in fruits.

How to use the refractometer

With the portable refractometer, any measurement requires that the prism surface and lid are clean. You can clean it with a damp cloth with warm water at 20ºC and isopropyl alcohol. The instrument must then be calibrated to zero, either with distilled water or with BRIX calibrating collusion. To carry out the measurement, you must place a few drops on the prism, and disperse the sample evenly avoiding the formation of air bubbles. Cover with lid and measure at room temperature. Observing through the eyepiece, if the equipment does not have LED it is possible to read under sunlight and focus with the help of the calibration screw until it is clear. Read the values where the measurement scale intercedes with the boundary line. Finally clean the instrument and store it in its case.

For each application there are a wide variety of references in refractive equipment. At Kalstein we are MANUFACTURERS, we have to offer quality refractometers and state-of-the-art technology. To learn more about the characteristics of our PRICES, the BUY or SALE can visit our website HERE