LimsPulse
Physical testing

Refractometer

Measures the refractive index of a liquid or melted solid, usually at 20 °C and 589 nm. It is a quick identity and purity test for oils, solvents and syrups.

  • Pharmaceutical
  • Food & beverage
  • Flavours & fragrances
  • Chemicals
  • Petrochemicals
Photo of a Refractometer
Photo: Roco190, CC BY-SA 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the calibration status and that the daily water check (if required) has passed.
  2. 2Switch on and set the prism temperature (usually 20.0 °C). Wait until it is stable.
  3. 3Clean the prism with a soft tissue and a suitable solvent, then dry it.
  • Never use abrasive tissues or metal tools on the prism.
STAGE 2

Measurement

  1. 1Place enough sample on the prism to cover it completely (usually a few drops).
  2. 2Close the cover to reduce evaporation and wait for the temperature to stabilise.
  3. 3Start the measurement (digital) or line up the boundary with the cross-hairs and read the scale (Abbe).
  4. 4Record the refractive index and the temperature.
  5. 5Clean the prism and repeat on a fresh portion; report the mean if your SOP asks for duplicates.
  • Solid samples must be melted or dissolved as the monograph describes.
  • Bubbles or undissolved particles on the prism give a blurred boundary.
STAGE 3

After use

  1. 1Clean the prism with a suitable solvent, then water if appropriate, and dry it.
  2. 2Close the cover and complete the log.
  • Remove oils and sticky syrups straight away; dried residues are hard to clean and can damage the prism seal.
In LimsPulse · Calibration Management

Keep every Refractometer in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how