Operation and Calibration of Polarimeter

1.0 OBJECTIVE

1.1 To lay down a Procedure for Operation and Calibration of Instrument in Quality Control Department.

2.0 SCOPE

2.1 This procedure is applicable for Operation and Calibration of Polarimeter

3.0 RESPONSIBILITY

3.1 QC Officer or QC Executive

4.0 ACCOUNTABILITY

4.1 QC Manager

5.0 Operating Procedure

5.1.1 Switch ‘ON’ the electric supply and within 10 minutes, the sodium lamp to glow optimally.
5.1.2 Check the polarimeter tube and its cabinet. It should be clean.
5.1.3 Position the incoming light source, polarimeter tube and cabinet in a line by rotating the revolving stand of sodium
lamp.
5.1.4 For clear vision of colour shade, adjust the upper and lower eyepiece to anterior and posterior side.
5.1.5 Fill the polarimeter tube with water/ blank in which the substance is dissolved and place this in cabinet. (determine
at Temperature 25°C, unless & otherwise specified in the procedure/monograph)
5.1.6 Rotate the knob at the anterior right and match the colour shade in both sections by observing in lower eyepiece.
5.1.7 Take the reading in upper eyepiece, it should be about zero, Rotate the Vernier scale at the left anterior head of
instrument. Add the reading of main scale and Vernier scale, and find the reading of rotation.

5.1.8 Fill the polarimeter tube with the liquid/prescribed solution. Solution/liquid should be clear and free from air-
bubble.

5.1.9 Rotate the knob for matching the colour shade similarly as step 5.1.6
5.1.10 Take the reading in + or – in upper eyepiece and note it. (Take three concurrent readings of blank as wel as
sample and consider the mean value.)
5.1.11 Deduce the reading of blank from the reading of sample, and calculate as follows-

CALCULATION :
Angular rotation x 100
——————————————
Length of tube (dm) x % of solution

5.1.12 After completion of reading, take out the polarimeter tube from its cabinet & clean. Keep it in its box. Then
switch off the instrument.
5.1.13 Do analysis activity entry in instrument log book.

5.2 Calibration Procedure
5.2.1 Dry the sucrose at 105°c for 4.0 hours and prepare the 10.0%, 20%w/v, 30% w/v, 40%w/v, and 50%w/v in
distilled water.
5.2.2 Fill the polarimeter tube with water/blank in which the substance is dissolved and place this in cabinet.
(Temperature should be 25°c)
5.2.3 Rotate the knob at the anterior right and match the colour shade in both sections by observing in lower eyepiece.
5.2.4 Take the reading upper eyepiece it should be about zero. Rotate the Vernier scale at the left anterior head of
instrument. Add the reading of main scale and Vernier scale, and find the reading of rotation.
5.2.5 Rinse the polarimeter tube with 10%w/v sucrose solution and note down the rive readings and calculate the
observed optical by rotation by following formula:-
Optical Rotation = (Observed angle of rotation x 10)/ Sample weight in grams
5.2.6 Repeat above procedure for 205w/v, 30%w/v, 40%w/v, and 50%w/v sucrose solution and record the data in
format calibration of polarimeter & affixed calibration label.
5.2.7 Calibration frequency: Quarterly.
5.2.8 Action to be taken upon failures: Contact the Q.C. head department.

6.0 ABBREVIATIONS

Abbreviation	Extended Form
QC	Quality Control
SOP	Standard Operating Procedure
°	degree
gm	gram
mg	milligram
dm	decimeter
dm	decimeter

Solution percent of Sucrose	Preparation of sucrose solution	Standard Angle of Rotation at 25ºC	Observed Angle of Rotation at 25ºC	Acceptance Criteria	Remark
10%	Weight of Sucrose=	+13.33º		+13.28º to 13.38º
20%	Weight of Sucrose=	+26.61º		+25.56 º to +25.66 º
30%	Weight of Sucrose	+39.86º		+39.81 º to +39.91 º
40%	Weight of Sucrose	+53.06º		+53.01 º to +53.11 º
50%	Weight of Sucrose=	+66.23º		+66.18 ºto +66.28 º

Operation and Calibration of Polarimeter

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