Refractive Index / Brix

When light passes from one medium to another, the speed at which the light travels will change depending on the parameters of the materials. This principle can be seen when looking at a straw in a glass or an oarsman on the river, where the straw or oar appears to be bent at the water/air interface.

The ratio or change in the speed of light is called refractive index and instruments that measure this are called refractometers. 

The refractive index of a liquid is related to its concentration and so a refractometer can display the concentration in suitable units, such as °Brix (sucrose), total dissolved solids (TDS), Baume, probable alcohol, sodium chloride, urea and urine specific gravity to name just a few. 

Refractometers are simple optical instruments used throughout industry for over 150 years and have now developed in to sophisticated digital instruments capable of measuring the % of dissolved solids to 3 decimal places.

  • Handheld
  • Benchtop

Bellingham + Stanley RFM300-M Refractometer

The all new RFM300-M series refractometers are the ultimate instruments for installation in demanding factory environments as well as for use as a primary quality control tool.

Digital Benchtop Refractometer with touchscreen and Peltier temperature control RFM300-T

Bellingham + Stanley RFM300-T Refractometers

The RFM300 now boasts a 7" touchscreen user interface with easy to use menus giving this powerful refractometer, suitable for harsh factory environments, a fresh modern look and feel.

RFM 900T Refractometers

Bellingham + Stanley RFM900-T Refractometers

The RFM900-T Series of Peltier temperature controlled refractometers combine latest opto-electronic principles with durability and ease of use via a touchscreen user interface.  Offering a wide refractive index range and high precision measurement to six decimals RI, the RFM970-T version is ideal for use in pharmaceutical applications operating in accordance with Pharmacopeia and FDA regulation 21 CFR Part 11; as well as in petrochemical, chemical, and aroma applications.

abbe5 refractometer

Bellingham + Stanley Abbe 5 Refractometer

The Abbe 5 is an affordable refractometer ideally suited for use where a wide refractive index measurement range is required such as in small contract laboratories or applications where sample throughput is relatively low. The instrument is also ideal for practical demonstrations and experiments in chemistry and physics laboratories of schools, colleges and universities and is the perfect partner to the new Model D7 optical polarimeter.