Standard Operating Procedure (SOP) for Operation and calibration of Polarimeter used to determine of optical rotation of raw material in Quality Control.
Procedure for Polarimeter – Operation and Calibration
1.0 Objective :
-
- To lay down a procedure for operating and calibration of Polarimeter. It is used to determine the optical rotation of material.
2.0 Scope :
-
- This SOP is applicable for operation and calibration of Polarimeter in Quality Control.
3.0 Procedure – Polarimeter:
-
-
What is Optical Rotation ?
- The optical rotation is the angle through which the plane of polarization is rotated when polarized light passes through a layer of a liquid.
-
-
- Optical rotation is the effect which is determined by the concentration of chiral molecules and their molecular structure in a substance
-
-
Operation Procedure for Polarimeter:
-
-
- Ensure that equipment & tube is clean.
-
- Check the calibration due date.
-
- Set up the instrument on the bench with the analyzer head facing the operator, an illuminated sodium lamp is attached with equipment through a bracket.
-
- Switch ON the mains.
-
- Switch ON the Sodium vapour lamp by pushing the switch of transformer downward. The red indicator will glow on transformer.
-
- Wait for five minutes so that Sodium vapour lamp gets illuminated completely.
-
- The position of Sodium vapour lamp is such that the field can be seen clearly while viewing through lower eyepiece.
-
- Adjust the lower & upper eye piece & focus it by sliding it towards your eye or away from your eye to view the clearly.
-
- After focusing the upper eye piece you will see the scale graduation & a vertical line called reference line.
-
- Rinse the tube with the solvent used and fill the tube with the solvent in such a manner that there should not be any air bubble.
-
- Place the tube in the cabinet and close it.
-
- Now see through the lower eye piece and match the colour shade to similar in both section by rotating the knob placed on the opposite to eye piece.
-
- Take the reading by viewing through upper eye piece.
-
- If the reference line do not concide with the scale then adjust with micrometer drum knob.
-
-
Take the five readings.
-
-
- Now rinse the tube with the solution and fill the tube with the liquid / prescribed solution and take reading following the procedure given above.
-
- Take the reading in + or -.
-
- Deduct the reading of solvent from reading of liquid/sample and calculate the specific optical rotation.
-
- After completion of work open the cabinet, remove the tube and clean it thoroughly.
-
- Switch off the Sodium vapor lamp.
-
- Enter the details in Instrument log.
-
Calibration Procedure of Polarimeter:
-
- Operate the equipment as per SOP.
-
- Weight accurately 50 g sucrose (previously dried) and transfer in 100 ml volumetric flask.
-
- Add 50 ml water (milli Q), shake well to dissolve and make up the volume with water (milli Q) (solution A).
-
- Rinse the tube (1-dm) with water (milli Q) and filled the tube with water (milli Q) after maintaining the temperature 25 ±1ºC.
-
- Set the null point with the help of knob adjustment and note the reading up to two decimal place with the help of linear and outer side.
-
- Rinse the tube with sucrose solution (A) and follow the steps in SOP and measure the angle of rotation.
-
- Similarly prepare solution of 40, 30, 20 and 10g/ 100 ml by diluting 20.0 ml, 15.0 ml, 10.0 ml, and 5.0 ml of solution (A) to 25.0 ml with water (milli Q).
-
- Measure the angle of rotation following steps of SOP and record the observation Annexure I.
-
- Take average of five readings for each concentration.
-
Acceptance criteria for Polarimeter Calibration:
Concentration (g/100ml) Angle of rotation (+) at 25ºC
10 6.66° ± 0.5
20 13.30°± 0.5
30 19.93° ± 0.5
40 26.53°± 0.5
50 33.11° ± 0.5
-
- Enter the details in Annexure I.
-
- Prepare the calibration tag and affix it on the Polarimeter.
-
- Enclose the old calibration tag with the record and don’t throw it.
-
-
If the variation is not within the specified tolerance limits:
-
-
- Label the Polarimeter equipment with a tag, “OUT OF CALIBRATION”.
-
- Inform the Department Head.
-
- Do not use equipment until all errors are rectified. After rectification, again calibrate the equipment & record the observation.
-
- Frequency: 6 Months ± 3 days.
-
-
Important:
-
-
- Fill the tube in such a manner that there should not be any air bubble.
-
- The temperature of solvent / solution should be 25°C ±1°C.
-
- Ensure that the solution is clear.
-
- Take five readings for each operation of Polarimeter.
-
- For any deviation in equipment inform to service engineer.
-
- For more details refer instruction manual.
Annexure I: Calibration Record of Polarimeter
Format for Calibration of Polarimeter
Make : ………………. Eq. No. : ……………….
Model No. : ………………. Calibration Frequency : 6 Months ± 3 days
Calibration Due on: ………………
Batch No. of Sucrose: ……………….
Stock Solution A: Dissolve ………………….. g. Sucrose in 100.0 ml (…………ml ) water (Milli Q)
Length of Polarimeter Tube: 1 dm | Light Source : Sodium Light (589.3 nm) | ||||||||
Volume Taken
(ml) |
Diluted to Volume
(ml) |
Concentration (%) | Angle of Rotation at 25°C | Acceptance criteria
(°) |
|||||
Observed | Average | ||||||||
5.0 | 25.0 | 10 | +6.66±0.5 | ||||||
10.0 | 25.0 | 20 | +13.30±0.5 | ||||||
15.0 | 25.0 | 30 | +19.93±0.5 | ||||||
20.0 | 25.0 | 40 | +26.53±0.5 | ||||||
Stock Solution A | ………. | 50 | +33.11±0.5 |
Remarks: The observed values comply / does not comply the acceptance criteria and the equipment can be / cannot be used for routine analysis.
Next calibration due date : …………………..
4.0 Reference(s) – Polarimeter SOP
-
- Manufacturer manual
-
- Chapter No. 2.4.22 of IP 2014
*****************************************END*****************************************