Operating, Cleaning and Calibrating Procedure for Polarimeter

1. OBJECTIVE
To lay down the procedure for operation, Cleaning and Calibration of Polarimeter

2. SCOPE
This procedure is applicable to Quality Control Department

3. RESPONSIBILITY
• Officer QC
• Manager QC

4. SAFETY INSTRUCTIONS
• Proper handling the instrument
• Don’t switch on the main board with wet hands

5. PROCEDURE
5.1 OPERATION
5.1.1 Switch “ON” the mains.
5.1.2 Adjust vernier scale to zero dial scale to zero.
5.1.3 View through the piece, if there is difference in intensity of light adjusts it without disturbing the dial reading by adjusting, the knurled screw of polarizing prism.
5.1.4 It is different to adjust with the knurled screw, adjust the dividing line by rating dial and vernier scale. Note down the reading, which is Dextro or Levo and will be taken as zero error for the calculation of optical rotation.
5.1.5 Rinse the polarimeter tube with the blank solution.
5.1.6 Fill the tube with reference solution at specified temperature.
5.1.7 Clean the sides of tube with tissue paper.
5.1.8 If any bubble comes it must be trapped in the center of tube.
5.1.9 Keep the tube in its place in the polarimeter.
5.1.10 Adjust the zero on the upper scale with the help of control wheel.
5.1.11 Focus circular disc of the light with the help of field telescope.
5.1.12 By means if control wheel, move the scale from its first position.
5.1.13 Observe the field which is divided into two valves, light and dark.
5.1.14 Adjust the control wheel to get the equal intensity of two halves.
5.1.15 If the index line between two scale divisions, therefore rotate the knurled wheel to bring the index line coincident with a scale line.
5.1.16 Note the reading in the degree of rotation.
5.1.17 Repeat the operation five times.
5.1.18 Consider the average reading.
5.1.19 Mark it as + (Plus) reading if it is left to the zero and – (minus) reading if it is right to the zero.
5.1.20 Remove the polarimeter tube from the polarimeter.
5.1.21 Discard the solution from the polarimeter.
5.1.22 Now same procedure is done for test solution.
5.1.23 After discarding test solution from the tube.
5.1.24 Switch “OFF” the main.
5.1.25 Wash the tube with distilled water if solutions are prepared in the polar solution or wash it with the methanol if it is prepared in non-polar.
5.2 CLEANING
5.2.1 After completion of testing, remove the polarimeter tube from the instrument.
5.2.2 Switch “OFF” the instrument.
5.2.3 Switch “OFF” the mains.
5.2.4 Remove the solution sample from the polarimeter.
5.2.5 Clean it thoroughly with water.
5.2.6 Wipe it with tissue paper.
5.2.7 Wipe the temperature probe with tissue paper.
5.2.8 Clean the instrument with cotton cloth.
5.3 CALIBRATION
Frequency: Monthly or after any maintenance
5.3.1 Switch “ON” the mains.
5.3.2 Wait till sodium lamp glows with the fully intensity of yellow light.
5.3.3 Rinse the polarimeter tube with distilled water.
5.3.4 Adjust the vernier scale and main dial scale to zero.
5.3.5 If two half intensity is no meeting then adjust it by turning the knurled screw of the prism box slightly. If not possible then adjust the field by rotating milled knob and vernier scale note the reading (+) or (-) side as zero and to be considered while calibrating.
5.3.6 Filled the distilled water in the polarimeter tube.
5.3.7 Clean the sides of tube with tissue paper.
5.3.8 Entrap any air bubble in space at center of tube.
5.3.9 Keep the polarimeter tube in the place provided in the polarimeter.
5.3.10 Adjust the zero with the help of control wheel.
5.3.11 Focus circular disc of light with the help of field telescope.
5.3.12 Observed the fields, which is dived into two halves light and dark.
5.3.13 Adjust the control wheel to get the equal intensity of the two halves.
5.3.14 Measure optical rotation of blank solution.
5.3.15 Note the +ve or –ve reading in the degree of rotation.
5.3.16 Repeat the steps five times and take average.
5.3.17 Remove the tube from the polarimater and discard the distilled water from it.
5.3.18 Prepare the 10%, 20%, 30%, 40% and 50% solution in distilled water of standard refined sucrose previously dried at 105 ̊C for 3 hours.
5.3.19 Rinse the tube with 10% solution and and fill the solution in the polarimeter tube.
5.3.20 Clean the sides of tube with tissue paper.
5.3.21 Entrap any bubble in the center of tube.
5.3.22 Keep the polarimeter tube in the space provided in the polarimeter and measure the optical rotation of sample solution.
5.3.23 Note the reading in the degree of rotation.
5.3.24 Repeat the operation five times and record the reading.
5.3.25 Remove the tube from the polarimeter and discard the solution from the polarimeter.
5.3.26 Repeat the operation with 20%, 30%, 40% and 50 % solution after rinsing the same solutions.
5.3.27 Note the reading of each concentration.
5.3.28 Remove the tube from polarimeter and discard the solution from the tube.
5.3.29 Wash the tube with distilled water and rinse with acetone and keep it in polarimeter tube box.
5.3.30 Switch “OFF” the mains.
5.3.31 Enter the calculated readings in the calibration record.
Acceptance Criteria: Difference between standard value and calculated value must not be more than 0.05̊ for 10% and 20% solution and not more than 0.1̊ for 30%, 40% and 50% solution.

6. RELATED DOCUMENTS
Operational Log Book Format – Annex. I
Cleaning Log Book Format – Annex. II
Calibration Report Format – Annex. III

7. DISTRIBUTION INDEX
Original Copy will be retained by Quality Assurance Department.

8. ABBREVIATIONS
Q.C Quality Control Department

9. REVISION HISTORY