Determination of sucrose by Polarometry

Polarimetry
In this short exercise we will measure the Optical Rotation of a solution of Sucrose, which will allow us to determine Sucrose’s Specific Rotation [?]. The specific rotation is a characteristic physical property associated with optically active molecules. We compare our measured value with the accepted value as reported in the literature. Nest, we will determine the specific rotation of the S-(+)-Ibuprofen isolated in last week’s laboratory. However, this sample may not be optically pure. The comparison of our “observed” specific rotation with the accepted value will allow us to determine the sample’s Optical Purity.
The angle of rotation will be proportional to the ability of the compound to rotate plane polarized light, or Specific Rotation [?], the Length of the polarimeter cell l, and the Concentration of the optically active compound c:
? = [?] l c
The specific rotation is a characteristic property of a given optically active molecule. If the specific rotation of a compound is positive, the compound is said to be dextroratory, if negative, it is referred to as levorotatory. Formally, specific rotation has units of deg dm-1 cm3 g-1. However, it is frequently reported simply in units of degrees.
Finally, for a sample that may be contaminated with the opposite enantiomer, the Optical Purity can be defined as:
Optical Purity = x 100