A new polarimetric technique that uses a narrow, collimated beam of laser light to differentiate between mirror image forms of asymmetric molecules has improved the sensitivity of classic devices and has ex- panded applications to solve a wide variety of problems in areas ranging from clinical medicine and pharmaceutical testing to research and development connected with commercial products.
Polarimetric analysis is based on the principle that asymmetric molecules are optically active—that is, they rotate the plane of polarized light in a clockwise (+) or counterclockwise (-) direction, depending on their arrangement of atoms. Many important molecules, such as sugars, pharmaceutical drugs, proteins, steroids, and organic compounds, exist in these two forms. Differentiating between them is important because very often only one stereoisomer is metabolically or chemically active.
All polarimeters operate by passing a beam of monochromatic, polarized light through a cell containing the sample and detecting the subsequent angular change, ...
