Under a particular set of conditions, the optical rotation of the compound provides a basic physical constant that is useful for identification, such as refractive index, boiling point, and melting point. Polarimetry is an important tool for identifying natural compounds such as alkaloids, steroids, carbohydrates and amino acids.
In this application, the change in optical rotation that occurs in the chemical transformation of a substance is estimated. Then, experiential correlations from the study of known structures are used to infer information about the unknown compost.
For the quantitative analysis of optically active compounds, polarimetric measurements are easily optimized. The experimental calibration curve is applied to relate the optical rotation to the concentration of an analyte. The sugar industry uses optical rotation for the quantitative analysis of sucrose.