Determination of refractive index by using Refractometer SOP


Title: Standard operating procedure for determination of refractive index by using Refractometer.


1.0                     OBJECTIVE:

To lay down the procedure for analysis on Refractometer.

2.0                     SCOPE:

This shall be applicable to the Refractometer of Quality Control Instrument Lab.

3.0                     RESPONSIBILITY:

3.1      Technical Assistant/ Helper.

3.2      Q.C Analyst.

4.0                     ACCOUNTABILITY:

4.1      Manager-Quality Control.

4.2      Head of the Q.C Department.

5.0                     MATERIAL AND EQUIPMENT:

5.1      Refractometer.

5.2      Glassware (according to requirement).

5.3      Sample.

6.0                     PROCEDURE:

6.1      Ensure that the area is clean.

6.2      Switch on the main power.

6.3      Set the temperature.

6.4      Open the prism and place approx. 2 drops of sample on the bottom prism.

6.5      Use care not to touch the prism surface with the dropper.

6.6      Close the prism carefully & place the lamp close to prism.

6.7      Adjust the eye piece cross wire with a knob by rotating it in a clockwise and anti-clockwise direction. So that the sharp demarcation line passes through its centre.

6.8      Sharp demarcation is produced in the form of circle having half light and half dark portion.

6.9      A knob can be adjusted to a fine adjustment.

6.10  Note down the reading from the scale with the help of the magnified lens of the instrument.

7.0                     REVISION LOG:

Revision No.

Effective Date





8.0                     REFERENCES:

8.1      The British Pharmacopoeia. Vol V., Official Monograph /Refractive index: 2015, pp. 244.

9.0                     ANNEXURES:

Annexure 1: Observations of Refractometer.



Annexure: 1

Observations of Refractometer

Apparatus: _____________________

Sample solution: _________________

Room temperature: ______________

Sr. #



Refractive index






















Remarks: __________________________________________________


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