3. Use in chemical analysis

3.1 Substances analyzable by refractometry

In the first place, refractometric measurements are only applicable to optically transparent media. However, for some methods, such as the boundary angle method, only a very small quantity of material is needed to make a suitable measurement. For example, even if a liquid or gel has an opaque or strongly tinted appearance by mass, a drop or thin strip of the substance will be sufficiently transparent for meaningful measurements to be made.

The method to be used to measure the index of a body depends on the state it is in.

• Solid

  Transparent solid materials (optical glasses, natural or artificial crystals) have refractive indices ranging from 1.3...