Calibration of Melting Point Apparatus

Procedure

1. Ensure that all the connections of the instrument are proper.
2. Operate the instrument as per the operating instructions and determine the melting point of the following reference substances.
3. Take the reference substances from lowest range to highest range at a time for calibration.

Reference Substances	Standard Range
Vanillin	81.0°C – 83.0°C
Acetanilide	114.0°C – 116.0°C
Urea (finely crushed)	132.0°C – 135.0°C
Sulphanilamide	164.5°C – 166.5°C
Caffeine (dried at 100°C)	234.0°C – 237.0°C
Diclofenac Sodium	277.0°C – 283.0°C

Acceptance criteria

The melting point of the reference substances should be within the standard range.

Frequency

Once in a month

Maintenance/ Repairs

When the instrument does not comply with the requirement/ tolerance range specified above, the instrument should be labeled “OUT OF CALIBRATION” and should be repaired/ serviced.
After repair/ maintenance, calibrate the instrument.