Calibration of Melting Point Apparatus
Procedure:-
3.3.3 Fill the capillary tubes with the testing sample VaN/Alin to give a compact column 4mm to 6mm in height. Place this capillary tube in the hole provided in the instrument.
3.3.4 When the temperature reaches within about 10°C below the expected melting point of substance, reduce the rate of heating Adjust the heating rate to about 1°C per minute.
3.3.5 Note down the temperature range at which the material starts to melt and last solid particle of a substance in the capillary tube passes into the liquid phase.
3.3.6 In the same way, repeat the procedure for Sulphanilamide and caffeine. Dry Caffeine at 100°C for three hours, before use.
3.3.7 The standard melting range of the reference substances is given in following table:
| Sr. No. | Reference Substance | Standard Melting range |
| 1. | Vanillin | 81° – 83°C |
| 2. | Sulphanilamide | 164.5°-166.5°C |
| 3. | Caffeine
(dried at 100°C) |
234°-237°C |
- Tolerance Limit: All the reference material should melt between their standard melting range.
Reference Substances detail:
| Sr. No | Reference Substance | Batch Number | Make |
| 1 | Vanillin | ||
| 2 | Sulphanilamide | ||
| 3 | Caffeine |
Observations:
| Sr. No. | Reference Substance | Observed Melting Range | Tolerance Limit | |
| 1 | Vanillin | 81° to 83°C | ||
| 2 | Sulphanilamide | 164.5° to 166.5°C | ||
| 3 | Caffeine | 234° to 237°C |
Remarks : Melting Point Apparatus is working Satisfactory/ Not Satisfactory
“End of Document”