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Definition of Polarimetric

Polarimetry is a method used to measure the optical activity displayed by a given compound. The term ̶0;polarimetric̶1; refers to techniques, measurements and procedures pertaining to the methods of polarimetry and can be used to refer to the ̶0;polarimetric method̶1; generally. The polarimetric method is well-established, and the U.S. Food and Drug Administration include polarimetric standards that some compounds must meet to be considered fit for consumption.

Polarimetry
- Certain compounds rotate the orientation of linearly polarized light that is passed through them. This is referred to as a change in ̶0;polarization orientation.̶1; This is called ̶0;optical activity,̶1; and it is caused by a one-enantiomer excess in a ̶0;chiral molecule.̶1; The measurement of this rotation is a nondestructive technique known as polarimetry and it is used to test the purity of various compounds in a wide range of industrial and academic fields.
Polarimeter
- Polarimetric measurements are obtained using a device called a polarimeter. These machines offer multiple wavelengths and high accuracy of detecting rotation in samples. Some devices have the capacity to heat or cool the sample to a given temperature, if this is required. Polarimeters have different features, accuracy and other specifications based on the purpose or industry they are intended to be used for. For example, an accuracy of 0.02 would not be considered appropriate in the pharmaceutical industry.
Research Applications
- The polarimetric method is used in research for a range of purposes. These include differentiating optical isomers, analyzing the molecular structures of compounds, monitoring variation in optically active components, studying kinetic reactions and identifying unknown crystallized compounds collected from solvents. It is also used to classify optically active compounds empirically, and then comparing the results with those predicted by the currently accepted scientific theories. In all of these processes, different wavelengths are employed during the polarimetric procedures.
Applications in Industry
- Polarimetry is most commonly used in quality and process control operations. In the pharmaceutical industry, it is used to measure the purity of various drugs, vitamins and aminos. In the flavor, fragrance and essential oil industries, it is used to check oils, gums and various types of acid. In the food industry polarimetry is employed on sugar-based foods, to measure the concentration of carbohydrates, lactose, starches, glucose and other sugars.

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