Melting Point Apparatus – SOP

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

4.0   RESPONSIBILITY – SOP FOR MELTING POINT APPARATUS:

    • Analyst shall be responsible for:Melting Point Apparatus

    • 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   ABBREVIATIONS & DEFINITION:

    • SOP : Standard Operating Procedure
    • LED : Light Emitting Diode
    • DEFINITION:

    • Melting Point: The melting temperature of a solid is defined as the point at which the solid coalesces and is completely melted.
    • Melting Range: The melting range of solid is defined as points of temperature within which the solid coalesces and gets completely melted.

6.0   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.

7.0   ANNEXURES – MELTING POINT APPARATUS:

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

Instrument Name Melting Point Apparatus
Instrument Code   Make/Model    
Location   Calibration frequency   Monthly ± 3 days
Calibration Date   Next 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 Standard Calibration Standard No. Observed Melting Range Limit
1 Vanillin     81°C to 83°C
2 Acetanilide     112°C  to 115°C
3 Sulfanilamide     163°C to166°C
4 caffeine     235°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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Janki Singh is experienced in Pharmaceuticals, author and founder of Pharma Beginners, an ultimate pharmaceutical blogging platform. Email: [email protected]

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