SOP for Operation and Calibration Procedure for Polarimeter

To lay down the procedure for operation and calibration of the Polarimeter (Make: Bellingham; Model No-ADP440+) for better and error-free use. 

This procedure is applicable to Digital Polarimeter installed in Quality Control Department, at  PharmaSky Limited.

Execution: Chemist and above – QC department. 
Checking: Asst. Manager and above – QC department

  • Plug in the power supply and switch on the mains. 
  • To switch on, press the power key-the power indicator will show green. 
  • Take a clean empty dry sample tube and place in the chamber. 
  • Wait for the instrument to stabilize, using the reading progress bar as a guide. 
  • When stable press ZERO. The displayed reading will now change to 0.00 
  • Fill the polarimeter tube with the sample. 
  • Gently rock the tube from end to end to ensure all air bubbles are released through the center filling 
  • Lift open the chamber cover and places the tube on the two rails 
  • You should notice that the reading fluctuates as it settles. Note that the progress bar will slowly fill, also as an indication that the reading has yet to stabilize, the reading result is displayed in grey. 
  • When finally stabilized the progress bar will appear full and the reading will be displayed in black. 
  • Take print out 
  • Switch the instrument to standby by pressing the power key and hold down until a confirmation screen shows (approximately 2 seconds). Press yes to switch to standby-the power indicator will show red, or press no to continue operating. 
  • Empty, clean and dry the sample tube. 

Note: It is preferable for the instrument to be left on continuously even if a reading is to be taken only once per day. More advanced use of the polarimeter might require that the instrument is zeroed with a sample (blank solvent) in the chamber 

  • Precautions 
  1. It is important that the chamber is empty while the instrument stabilizes. 
  2. While filling the polarimeter tube, care should be taken to avoid air bubbles in the path of a light source 
  3. Liquids and solution of solid must be clear 

Frequency: Quarterly 
  • Prepare 10%, 20%, 30%, 40% and 50% w/v aqueous solution of AR grade sucrose (previously dried) in water. 
  • Now fill the sample cell with the solvent (water) and press the “Zero” key to make the interference due to solvent as zero. Henceforth fill the cell with the 10% w/v sucrose solution and take the reading 
  • Repeat the above step for other remaining sucrose solutions and take out the print for each concentration. 
  • Record the observations in Annexure - 1 and calculate the correlation coefficient between concentration and the mean value of Optical Rotation. 

SOP : Standard Operating Procedure 
Q.C : Quality control 

Annexure No.-1 -- Calibration Record of Polarimeter


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