Standard Operating Procedure (SOP) for Operation and Calibration of Melting Point Apparatus used for analysis / identification  of starting materials (Raw Material – API & Excipient) in Quality Control Laboratory.

Operation and Calibration of Melting Point Apparatus

1.0   PURPOSE:

  • The purpose of this SOP is to describe the procedure for operation, calibration and maintenance of Melting Point Apparatus.

2.0   SCOPE:

  • This SOP is applicable to the following Melting point apparatus at Quality Control Department in pharmaceutical for Make : Polmon and Model MP-96.

3.0   REFERENCES – SOP FOR MELTING POINT APPARATUS:

  • Operation Manual supplied by the manufacturer
  • SOP for  Maintenance of Laboratory Instruments
  • SOP for Preparation of internal and external (Third Party) Calibration schedule and  calibration practices   

4.0   RESPONSIBILITY – SOP FOR MELTING POINT APPARATUS:

  • Analyst shall be responsible for:
  • To operate the instrument as per the SOP.
  • Calibrate the instrument as per the SOP.
  • To carry out the documentation as per the SOP.
  • Quality Control Head or Designee shall be responsible for :
  • To approve the calibration of instrument verifying against SOP.
  • To provide training to all the concerned persons before implementing the SOP.
  • Execute the out of calibration in case of calibration failure and in case of breakdown, intimate to Quality Head.
  • To ensure the operation and calibration of the instrument is carried out as per the SOP.
  • To ensure proper documentation as per the SOP.
  • Quality Assurance shall be responsible for:
  • To ensure the implementation of the system as per the SOP.

5.0   PROCEDURE – MELTING POINT APPARATUS:

  • General Procedure for handling of Melting Point Apparatus
  • Follow the SOP on Instrument/Equipment usage log book, for the entry of usage of the instrument. 
  • In case of any maintenance of instrument, follow SOP on Maintenance of Laboratory Instrument.
  • Maintain the third party calibration schedule and the internal calibration schedule for the instrument as per SOP, Preparation of internal and external (Third Party) calibration schedule and calibration practices.
  • Operational procedure
  • Check the calibration status of the instrument.
  • Switch ON power supply by switching on the main supply and switch provided on backside of the instrument.
  • Press the “FUNCTION” Key to set initial temperature. The “INI TEMP” LED blinks and parameter is displayed in the display.
  • Use “↑ ” or “ ↓ “ keys to set the initial temperature.
  • Set the initial temperature to 10°C below the expected melting point and the initial temperature should be (15 – 25 )°C above the bath temperature to overcome undershoot or overshoot of temperature, the maximum melting range for the operation of the instrument is 350°C.
  • Press the “FUNCTION” key to set “°C/min”, “°C/min” LED blinks and the parameter is displayed in the display.
  • Use “↑” or “↓” keys to set the rate of heating.
  • Press “FUNCTION” key. The bath temperature is displayed.
  • Press “START” key. The “INI TEMP” and “°C/min” LED blinks one after another displaying the corresponding setting with an interval of 2.5 sec.

NOTE: Be sure about the settings (initial temperature and °C/min) as they cannot be viewed or changed while heating process is ON.

  • Press “START” key. The oil bath temperature is raised to the initial   During this period “INI TEMP” LED glows continuously and “HEATER” LED glows continuously or blinks.
  • Insert the capillaries in the bath.
  • Press “FUNCTION” key to start Rate of heating (i.e. °C/min). During this period “°C/min” LED glows continuously and “HEATER” LED blinks.
  • Watch the sample through magnifying lens.
  • Press “STORE” key at the beginning of Melting point, “T1” LED glows continuously indicating that initial melting temperature is stored.
  • Press “STORE” key again to store final melting point. “T2” LED glows continuously indicating that final melting point temperature is stored.
  • To view initial and final melting point temperatures press “STORE” key to view initial melting point temperature, “T1” blinks to indicate that the displayed temperature is initial melting point.
  • Press “STORE” key again to view final melting point temperature, “T2” LED blinks to indicate that the displayed temperature is final melting point  
  • Calibration Procedure of Melting Point Apparatus
  • Calibrate by using Melting Point reference standard.
  • Calibration Frequency: Monthly ± 3 days.
  • The four Melting Point standards Vanillin, Caffeine, Acetanilide and Sulfanilamide shall be used.
  • Reduce the reference standard to very fine powder.
  • Treat the reference standards as given below:
  • Vanillin: Do not dry.
  • Caffeine: Dry portion over silica gel for 16 hours.
  • Sulfanilamide: Dry portion over silica gel for 16 hours.
  • Acetanilide: Dry portion over silica gel for 16 hours.
  • Charge the capillary, one end of which is sealed with sufficient quantity of reference standard to form a column in the bottom of the tube 2.5 mm to 3.5 mm height when packed down as closely as   possible by moderate tapping on a solid surface. Surface. (There should not be gap in the column).
  • Heat the block until the temperature is about 10°C below the expected melting point and continue heating at a rate of temperature increase of about 1° C per minute.
  • Insert the capillary tube in the melting point apparatus when the temperature is about 5° C below the lower limit of the expected   melting range and continue heating until melting is complete. 
  • Follow the above steps given in the procedure part.
  • Note the melting point of the reference substance.
  • Record the same in the calibration record.

6.0   ANNEXURES – MELTING POINT APPARATUS:

Annexure -1 : Format for Calibration Record of Melting Point Apparatus

Instrument NameMelting Point Apparatus
Instrument CodeMake/Model  
LocationCalibration frequency  Monthly ± 3 days
Calibration DateNext Calibration due on

Procedure

  • Reduce the standard to very fine powder or as recommended on the label of respective reference standard.
  • Treat the reference standards accordingly.
  • Charge the capillary, one end of which is sealed with sufficient quantity of reference standard to form a column in the bottom of the tube 2.5 mm to 3.5 mm height when packed down as closely as possible by moderate tapping on a solid surface. (There should not be gap in the column.)
  • Heat the block until the temperature is about  10° C  below the expected melting point and continue heating at a rate of temperature increase of  about 1° C per minute.
  • Insert the capillary tube in the melting point apparatus when the temperature is about 5°C below the lower limit of the expected melting range and continue heating until melting is complete.
  • Record the temperature at which the last particle passes into the liquid phase.
  • Remove the capillary tubes care fully and dispose it off after cooling.

Observation Table:

Sr.No.Melting Point StandardCalibration Standard No.Observed Melting RangeLimit
1Vanillin81°C to 83°C
2Acetanilide112°C  to 115°C
3Sulfanilamide163°C to166°C
4caffeine235°C to 239°C

Remarks : The instrument is calibrated & qualified / Out of calibration & not qualified for use.               

Calibration : Scheduled / Not scheduled ( Reason : ______________________

Annexure -2 : Format for Calibration Status label

CALIBRATION STATUS
Instrument :       ___________________________           ___________ Code :     ___________________ Model:  ______________________ Frequency______________________________________________ Done on :  ____________________________ Due on :____________ Status : Instrument found satisfactory for analytical use Done By : __________________________  Checked By :  __________ Date :    ___________________________   Date : ________________

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