Melting Point Apparatus - Operation & Calibration

Melting Point Apparatus

SOP FOR OPERATION

1.0 OBJECTIVE

To lay down a procedure for operation and calibration of melting point apparatus.

2.0 SCOPE

This SOP Covers the operation and calibration procedure of melting point apparatus and is applicable to Quality Control Department.


3.0 RESPONSIBILITY

Officer / Executive.

4.0 ACCOUNTABILITY

Department Head


5.0 PROCEDURE


5.1 PROCEDURE FOR GENERAL CLEANING

5.1.1 Ensure that the power supply to the instrument is switched ‘ OFF’ before cleaning

5.1.2 De-dust the instrument daily externally with a clean dry cloth.

5.1.3 Once in a week remove adhered dust by wet mopping using detergent solution. Afterwards wipe the surface with a clean dry cloth to remove traces of detergent.

5.1.4 Precaution has to be taken to clean the instrument immediately with dry cloth to remove the moisture.

5.2 PROCEDURE FOR OPERATION

5.2.1 Keep the ‘HEATER’ & ‘STIRRER’ Knobs to ‘MIN’.

5.2.2 Switch on the Main power supply. Switch on the ‘MAINS’ of the instrument.

5.2.3 The display will show some random figure, then press the ‘RESET’ push button to display the actual temperature of the furnace.

5.2.4 Keep the melting point tube in silicone oil containing glass container. . Check through the lense type mirror about the capillary is correctly seated in its cavity.

5.2.5 Turn the STIRRER knob slowly towards MAX. Press the START push button.

5.2.6 Turn the heater knob to MAX and put HEATER HIGH/LOW switch to HIGH. ( This switch is provided on right hand side of the instrument ). The raise of temperature can be controlled by using this switch and the HEATER knob.

5.2.7 When the temperature reaches within about 30 o C, of the expected melting point, reduce the rate of heating and adjust the rate of rise of temperature to about 1 o C, per minute.

5.2.8 Wait till the melting point is reached which is indicated by sample is melted in the tube. The digital read-out will display the exact temperature at which the sample is melted. Record this temperature. Turn off the ’HEATER’ Knob.

5.2.9 After reducing the temperature, switched off the instrument .

5.3 PRECAUTIONS

5.3.1 Care should be taken while inserting the capillary into its cavity or taking out from the cavity to avoid breaking, take it out vertically.

5.3.2 Check always colour of the silicone oil. Normally it is colourless. If it observed as yellow or brown, discard the oil. And take fresh oil in that container.

5.4 CALIBRATION PROCEDURE

5.4.1 Follow the cleaning procedure mentioned in the steps 5.1 to 5.4.

5.4.2 Check the melting points of the following Reference Standards as per the steps of operating procedure 5.2.1 to 5.2.9.

Standard Benzoic acid USP RS
melting range 121.0°C - 123.0°C
Standard Caffeine USP RS
melting range 235.0°C – 239.0°C

5.4.3 Record all the results in the calibration record as per Annexure – I.

5.4.4 Affix a ‘CALIBRATED’ label on the instrument

5.4.5 Report any discrepancy observed during calibration or operating the instrument to Department Head and notify the defect to utility 
     department to rectify the defect. Affix “BREAK DOWN” label on the instrument till it get rectified.

5.4.6 Frequency of calibration

Once a month and after each maintenance job.

6.0 Acceptance Criteria

The melting point of reference standard should be within limit mentioned in the calibration procedure as melting range.

7.0 REASON FOR REVIEW:

First time issue.