General Test Procedure Specific Optical Rotation

Purpose
1. This procedure is applicable to all incoming materials.
Apparatus
1. Polarimeter
2. Polarimeter Tube
3. Calibrated Balance
4. Thermometer
Reagents
1. None
Procedure
1. The optical rotation, a, unless otherwise specified, is measured at the wavelength of the sodium D-line

(589.3 nm) at a temperature of 25° in a layer 1 dm thick.

Dextrorotation is designated (+) and laevorotation is designated (-).

1. The specific optical rotation of a liquid is determined by measuring the angle of rotation at the

wavelength of the sodium D-line at a temperature of 25°, unless otherwise specified, calculating the

optical rotation with reference to a layer 1 dm thick and dividing by the relative density at 25°.

1. The specific optical rotation of a solid substance is determined, using the solution specified in the

monograph, by measuring the angle of rotation at the wavelength of the sodium D-line at a

temperature of 25°, unless otherwise specified, and calculating the result with reference to a layer 1

	Connect power plug to proper power supply through voltage stabilizer.
	Switch on main power supply & on the instrument by main ON / OFF Button; allow 15 minutes for the Sodium lamp glow up.
	Weigh accurately a suitable quantity of the substance in to a volumetric flask. & Prepare the solution in water, or other solvent, if specified in the monograph, reserving a portion of the solvent for the blank determination.
	Transfer the prepared solution/or liquid sample to the Polarimeter tube of required length (1dcm or 2dcm) within 30 minutes from the time of solution prepared & maintain the solution / liquid sample at a temperature of 25ºC.
	Polarimeter tube should be filled in such a way as to avoid air bubbles interfere with the passage source of light.
	Determine the Zero point of the Polarimeter and then take at least five readings at 25ºC with the test solution. Take an equal number of readings in the same tube with the blank solution. The blank reading is subtracted from the average observed reading of test solution.
	Calculate the specific optical rotation of a liquid substance, or of a solid in solution on dried basis.
	Lens of Polarimeter tube should be thoroughly cleaned before taking the reading.
	Polarimeter tube should be clean properly with distilled water.
	Lastly off the switch of voltage stabilizer and main power supply.