Principles of Polarimetry

Polarimetry measures the rotation of polarized light as it passes through an optically active fluid. The measured rotation can be used to calculate the value of solution concentrations; especially substances such as sugars, peptides and volatile oils. A polarimeter consists of a polarized light source, an analyzer, a graduated circle to measure the rotation angle, and sample tubes.

The polarized light passes through the sample tube and exhibits angular rotation to the left (-) or right (+). On the side opposite the polarizer is the analyzer. Using optics, visual fields are manually adjusted by the user to measure the optical rotation angle.

Polarimeters offer high accuracies where precision is critical in determining the concentration of samples. Cole-Parmer offers manual polarimeters where you look through a viewing scope to read values on a vernier scale, and semiautomatic polarimeters that have a digital display. Polarimeters can measure in angle of rotation (¡), International Sugar Scale (°Z), or both.