Polarimeter

1. Preparing the Polarimeter

1. Turn on instrument and let it warm up for 10 min.
2. Make sure instrument is set to "optical rotation" mode.
3. Prepare a blank sample in the polarimeter cell (1.5 mL total sample volume, 1 dm in length) containing only CHCl₃. Make sure there are no air bubbles present.
4. Place the blank cell in the holder and press "zero."

2. Preparation of Analyte Sample

1. Prepare a stock solution of 10-15 mg of the chiral analyte in 1.5 mL CHCl₃. Note the exact amount of compound used.

3. Measuring Optical Rotation

1. Fill the cell with 1.5 mL of the prepared stock solution containing the sample.
2. Place the cell in the holder and press "measure." The machine readout will give the optical rotation value. Remember to record the temperature as well.

4. Calculation of Specific Rotation

1. The specific rotation of a compound is defined by the following equation:
   
   where α is the optical rotation value given by the polarimeter, l is the cell pathlength in dm, and c is the concentration of the solution in g/mL.