Study Set Content:
Handheld
Digital
Benchtop
Abbe Refractometer
ABBE REFRACTOMETER Parts:
upper prism
lower prism
eyepiece
is firmly mounted on a bearing that allows its rotation by means of the side arm shown in dotted lines
upper prism
of the telescope is provided with crosshairs: in making a measurement, the prism angle is changed until the light-dark interface just coincides with the crosshairs
eyepiece
is hinged to the upper to permit separation for cleaning and for introduction of the sample
lower prism
Telescope
measuring prism
sample
illuminating prism
Matted surface
light source
is basically an Abbe type of refractometer of short range and without an illuminating prism.
immersion or dipping refractometer
It is used primarily for determining solution concentrations, such as in the sugar industry, pharmaceuticals, and milk.
IMMERSION REFRACTOMETER
• Particularly useful for acids since only the inert prism dips into the solution
IMMERSION REFRACTOMETER
It relies on having () of known refractive index and comparing the unknown mineral to the oil.
immersion oil
Immersion oil is available with refractive indices that cover the range found for most
minerals
It typically has indices of refraction in the range of
1.4 to 1.8
It typically has indices of refraction in the range of 1.4 to 1.8, in increments of
0.002, 0.004 or 0.005.
There are two components to comparing the index of refraction of the mineral and the immersion oil:
1. Relief
2. Becke Line
