Refractometer SOP


Primary Equipment:
Refractometer
Created: August 24, 2006 by Bob Cox
Revised: February 24, 2010 by Bob Cox

University of Utah, Chemical Engineering


  1. Set the bath temperature to 20 degrees C.
  2. Open the prism and place approximately two drops of the liquid sample on the bottom prism. Use care not to touch the prism surface with the dropper. Common samples are 2-proponol and ethylene glycol. Check with lab instructor to insure you have the correct sample.
  3. Close the prism case and place the lamp close to the prism. Turn on the lamp.
  4. Adjust the hand wheel on the right side of the instrument until the viewer appears light above and dark below the center horizontal line.
  5. Adjust the compensator dial on the front until the image in the viewer shows a sharp line between light and dark.
  6. Adjust the hand wheel on the right side until the horizontal line in the viewer passes between the crosshairs.
  7. Depress and hold the switch on the left and read the R.I value.
  8. Clean the prism with acetone and a Kimwipe.