SOP For operation & calibration of Refractometer

1. OBJECTIVE:

To lay down a procedure for Operation & Calibration of refractometer

• SCOPE:

This procedure is applicable for procedure for Operation & Calibration of refractometer.

• RESPONSIBILITY:

QC Officer/ QC Executive

• ACCOUNTABILITY:

QC Manager.

• PROCEDURE:
  • Operating Procedure
    • Ensure that instrument is clean and free from dust.
    • Switch ON the mains.
    • Open the prism box for measurement of refractive index of the sample.
    • Place 2-3 drops of sample on the ground surface of lower prism.
    • Close and fit the prism box.
    • Focus the cross wires of eyepiece by adjusting screw.
    • Adjust the mirror till good illumination is obtained.
    • Gently turn the prism box by means of milled head screw clockwise or anticlockwise till a colored band appears in the field of view.
    • Turn the milled ring at the base of telescope clockwise or anticlockwise where colored band is illuminated and a sharp dividing line is seen. Which divides a field of view in half illuminated and a half dark position.
    • By means of milled head screw, adjust the dividing line exactly at the intersection of   the cross wire.
    • Read the refractive index on the divided arc by means of magnifier to the third decimal point and fourth decimal on the milled ring at the base of telescope.
    • Note down the reading, which is the refractive index of the sample.
    • Open the prism box. Wipe off the sample with moistened tissue paper 2-3 times and dry the prism with dry tissue paper. Close the prism box and keep instrument in its cabinet securely.
    • The cleanliness of the instrument should be checked before use by determining the refractive index of distilled water which at 25°C is 1.3320 – 1.3330.
  • Calibration
    • Operate the instrument as mention in the operation procedure.
    • The instrument should be checked by determining the Refractive Index of distilled water at 25^oC.
    • If the refractive index of distilled water at 25^oC is not between 1.3320 – 1.3330, adjust the small square screw and at the back of telescope with the key provided with instrument. Bring the reading setting to 1.3325 and adjust the diving line exactly at the intersection of the cross wire by turning the key clockwise or anticlockwise, remove the key.
    • The instrument shall be further checked by determining the refractive index of the reference liquids. (Carbon Tetrachloride, Toluene, Distilled Water) & record.
    • Tolerance

Name of Reagents	Specification
Carbon Tetrachloride at 20°C	1.4600 to 1.4610
Toluene at 20oC	1.4940 to 1.4970
Distilled Water at 25oC	1.3320 to 1.3330

• Calibration Frequency – once in month.
• Fill the calibration status on metallic calibration label of the instrument; record the calibration result.
• If instrument is out of calibration, affix “UNDER MAINTENANCE “or “DO NOT USE” label on the instrument and immediately inform to maintenance & call service engineer.
• TRAINING:

Trainer   : Manager – Quality Control

Trainees : Staff of the QC departments

• DISTRIBUTION:

Master Copy                  :           QA Department

Controlled Copy            :           QC Department

Display Copy                 :           QC Department (If Required)

• ATTACHMENTS:

NA

• REFERENCES:

In-House

1. ABBREVIATIONS:

Abbreviations	Extended Form
SOP	Standard Operating Procedure
NA	Not Applicable
QC	Quality Control
Sr. No.	Serial Number
QA	Quality Assurance
DEPT.	Department
0C	Centigrade
RI	Refractive Index

1. REVISION HISTORY OF CHANGE:

Sr. No.	Date	Revision Details	Revision No.
01	15/0/2020	NEW SOP	00