Melting Point Apparatus – Operation & Calibration

Standard Operating Procedure (SOP) for Operation and Calibration of Melting Point Apparatus in Quality Control Laboratory.

Melting Point Apparatus

1.0   Objective :

    • To lay down a procedure operation and Calibration of Melting Point apparatus.

2.0   Scope :

    • This SOP is applicable for operation and calibration of Melting point apparatus in Quality Control.

3.0   Procedure : Operation and Calibration of Melting Point Apparatus :

    • OPERATION – Melting Point Apparatus:

    • Ensure that Melting Point Apparatus is clean and free from dust.
    • When the Melting Point Apparatus is Powered On or Reset key is pressed, it gets initialized and display reads,


MODEL: MR-Vis+ Version: V X.X

1) Prog 2) Run 3) Print 4) Config T°C: XX.X 

    • Main Menu Functions of Melting Point Apparatus software.

Prog’: To Add (create) / edit, view, copy, delete programs.

Run’: To start the RUN desired program for Melting range determination.

Print’: To view the results of last sample Run ; To obtain a hard copy of program parameter listing, Result report, Graph print out (for AUTO operation only) & Calibration  report.

Config’: To set date & time and to select data transfer to PC/Printer.

    • Procedure for the operation of Software – Melting Point Apparatus :

    • Turn on the Melting Point Apparatus system and windows shall display EDC icon
    • Then double click the icon EDC icon for further proceeding
    • After opening the icon on window, window will display another screen showing LABINDIA EDC 21 as shown below in the image.

    • Go to the file and file shall display four options as user Account Window, Front Panel, Audit Trial and Exit.
    • Then double click on front panel for the next step.
    • After opening front panel, window shall display front panel screen.
    • Then click Connect Option
    • After connecting the Melting Point Apparatus instrument new screen shall open requiring User Name and Password.
    • Then go to the Instrument Name shown as MRVIS +.
    • After clicking MRVIS + option bulb shall glow green and it indicates right selection of the Melting Point Apparatus instrument under operation.

Related : SOP for Moisture Analyzer Balance

    • Ensure following before the Sample Analysis run is Started on Melting Point Apparatus.
      • The round Cover-slip on the Furnace Lid is clean (not foggy)
      • The surface of the Furnace shall be clean from any foreign particles for a good thermal contact of the slide.
      • The presence of foreign particle will create the thermal difference and leads to erroneous results.
      • There shall not be Direct Air Draft in the furnace direction.
    • To Select ‘RUN’ from main menu options press ‘2’.
    • The Lamp will be switched ON automatically as soon as the Furnace temperature reaches 5°C below Set Temperature.
    • In AUTO operation, as soon as the sample starts melting, the Photo Sensor detects the start and instrument automatically records it and displays this temperature as ‘Set Temperature’ Display reading,
    • After melting of sample test is getting completed out, now, print the result by selecting the concerned results.

    • Frequency :  6 Month ±3 days
    • Tolerance:
1 Vanillin 81°C to  83°C
2 Sulphanilamide 163.5 °C to166.0°C
3 Acetanilide 114 °C to 116°C
4 Caffeine 234°C   to    237°C
    • Set The Method Using Following Parameter:

    • Select program from main menu options by pressing <1> key.
    • Select ADD from menu by pressing 1 and enter by pressing enter button.
    • Obtain program no., say 1 and press enter key.
    • Enter sample name by using alphanumeric keys and then press enter.
    • Select the sample preparation type by selecting 1 for Slide and 2 for Capillary and then press enter.
    • Select mode of heating by selecting 1 for Heat mode and 2 for Heat & Cool mode and then press enter.
    • Ten select operation (1) Auto (2) Manual and press enter key.
    • Use numeric keys to enter set temperature value & press enter key.
    • Enter the Furnace temperature cut off limit using numeric keys.
    • Enter heating rate 1ºC.
    • Press escape to return to main menu screen.
    • Ensure the sample is in the form of fine powder.
    • Use only standard capillary tubes with one end sealed.
    • Take the fine powder of vanillin about 3 to 4mm height in capillary tube and packed down as closely as possible by moderate tapping on a solid surface.
    • Operate the instrument and set the melting range of vanillin.
    • Keep the capillary tube filled by vanillin; wait for the material to melt and after sometimes instrument display the melting range of vanillin.
    • Repeat the procedure for Acetanilide, Sulfanilamide and Caffeine respectively.
    • Enter details in instrument log book.
    • Record the observation in Annexure – I
    • Prepare the calibration tag and affix it on the equipment.
    • Enclose the old calibration tag with record and don’t throw it.
    • If the variation is not within the specified tolerance limit:

    • Label the equipment with a tag “out of calibration”
    • Inform to the department head
    • Don’t use equipment until all errors are rectified

Related : Handling of Out of Calibration 

    • After rectification ,again calibrate the equipment and record the observations
    • If any discrepancy is observed during calibration or operation of the instrument affix the under maintenance label on the instrument.

4.0   Annexure

Annexure – I  : Calibration Record of Melting Point Apparatus

Make                         : ……………….                                  Eq. No.                                   : ……………….

Model No.                 : ……………….                                  Calibration Frequency         : 6 Month ± 3 days

Date of Calibration  : ………………

Sr. No. Reference Standard Sample detail Observed Melting Point (°C) Limit
1. Vanillin B. No.:

Mfg. Date:

81 – 83°C
2. Acetanilide B. No.:

Mfg. Date:

114 – 116°C
3. Sulphanilamide B. No.:

Mfg. Date:

164.5 – 166.5°C
4. Caffeine B. No.:

Mfg. Date:

234 – 237°C

Remarks: The observed values comply / does not comply the acceptance criteria and the equipment can be / cannot be used for routine analysis.

Next Calibration due date             : ………….


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