Polarimeter
Definition and meaning of Polarimeter in chemistry.
A polarimeter is a scientific instrument used to measure the angle of rotation caused by passing polarized light through an optically active substance. It is commonly used to identify and quantify chiral molecules in solution.
In more detail
Certain molecules, known as chiral molecules, lack a plane of symmetry and have the unique ability to rotate the plane of plane-polarized light. When polarized light passes through a sample tube within the polarimeter, the optically active substance rotates the light's plane by a specific angle. The instrument measures this angle of rotation, which depends heavily on the concentration of the substance, the path length of the sample tube, the ambient temperature, and the specific wavelength of light used. This measurement is vital for determining the purity and concentration of sugar solutions and various pharmaceutical compounds.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Purpose | Measuring optical activity |
| Target substances | Chiral molecules |
A polarimeter can be used to determine the concentration of a sucrose solution by measuring exactly how much it rotates plane-polarized light.
Frequently asked questions
What is specific rotation?
Specific rotation is a standardized measure of a substance's optical activity, calculated from the observed rotation by accounting for the sample concentration and cell path length.