STANDARD OPERATING PROCEDURE CALIBRATION OF THERMOMETER USED IN MELTING POINT APPARATUS

 STANDARD OPERATING PROCEDURE

 

SUBJECT:                      CALIBRATION OF THERMOMETER USED IN MELTING POINT APPARATUS

DEPARTMENT           : QA SOP NO.                      : Page No                       : Effective Date             : Next Review                :  SOP REVISION          :

1.0       OBJECTIVE:

To provide guidelines for Calibration of Thermometer used in melting point Apparatus.

2.0       POLICY:

Periodically Calibrated thermometer will be used for melting point apparatus.

3.0       PROCEDURE:

3.1       Thermometer used in the melting point apparatus is to be calibrated depending upon the melting point of substance under test.

3.2       Switch on the Melting point apparatus.

3.3       The melting point apparatus is standardized with the following standards of different melting range, these standards are previously dried at 105º C

                        S #       Material                     Melting Range (ºC)

                        01        Vanillin                        81.0-83.0

                        02        Acetanilide                  114.0-116.0

                        03        Sulphanilamide                        164.5-166.5

                        04        Caffeine                      235.0-237.5

           

3.4       Reduce the standards to a fine powder & dry over a suitable dessicator for not less than 16 hours.

3.5       Introduce this powder in the capillary tube sealed at one end.

3.5         Fill the powder in the capillary tube in the form of compact column of about 3 mm in height.

3.7    Start heating till the temperature reaches 10 deg. C below the expected melting point of the substance.

3.8        Continue the heating to rise the temperature at the rate of 3deg.C per min.

3.9       When the temperature is about 3 deg. C below the lower limit of expected range reduce heating so that the temperature rises at the rate of 1-2 deg. C per min.

3.10     Continue the heating till the sample inside the capillary melts along the sides of the walls at any point.

3.11     When the solid starts melting note the temperature and also note reading when the solid melts completely.

3.12     These two temperatures gives the Melting Range and the Thermometer should indicate the temperature as mentioned.

3.13     If the temperature shown in the thermometer is in the given range the thermometer is said to be ok and melting point apparatus is within the limits.

3.14     External Calibration is done for thermometer. Once a year & the report is maintained.

4.0       FREQUENCY:  Once in three months (internal).Once a year by External Agency.

5.0       RESPONSIBILITY:    Executive (QA)

6.0       REVIEW GUIDE: Calibration Record.

7.0       ANNEXURE: --------

6.0         SOPs DISTRIBUTION:

            This SOP shall be distributed to following Departments:

Name of the Department	Master Copy	Circulatory Copy
QA/QC	√	√
Production	x	×
Warehouse	x	×
General	x	×
Maintenance	x	×