Calibration of Digital Polarimeter

Ensure that all the connections of the instrument are proper.
Turn main power supply ON.
Prepare a solution of different concentrations by using sucrose A.R. grade previously dried at 105°C for 1 hour as follows:

Sr. No.	Concentration of Sucrose (in %)	Weight Taken (in g)	Dilution Volume with water (ml)
1	10	10.0	100
2	20	20.0	100
3	30	30.0	100
4	40	40.0	100
5	50	50.0	100

Enter the actual concentration with respect to the weight taken in MODE: 1. Measure the angular rotation obtained, calculate RSD% for 5 readings obtained in each concentration, calculate the correlation coefficient for different concentration [Refer Annexure 1].
Checks reading obtained with annexure for acceptance criteria.

Precautions

Check solution temperature.
While filling polarimeter tube due care should be taken to avoid air bubble in the path of the light source.
While using tubes with removable end plates fitted with gasket tighten end plate only enough to ensure a leak-proof seal between the end plate and the body of the tube.
Liquids and solutions of solid must be clear.
Frequency – Once a month
Related: Determination of Optical Rotation and Specific Optical Rotation

ANNEXURE-1

Sr. No.	Concentration of Sucrose (In %)	Optical Rotation (µ) At 25°C	Tolerance
			Minimum	Maximum
1.	10.0	13.33°	13.18°	13.40°
2.	20.0	26.61°	26.36°	26.80°
3.	30.0	39.86°	39.54°	40.20°
4.	40.0	53.06°	52.72°	53.60°
5.	50.0	66.23°	65.90°	67.00°

ACCEPTANCE CRITERIA FOR RSD %: Not more than 1.0%
ACCEPTANCE CRITERIA FOR CORRELATION COEFFICIENT: Not less than 0.995
REFERENCE
Indian Pharmacopoeia & United States Pharmacopoeia

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