Sop for Operation and Calibration of Micropipette

This Document describes (Standard Operating procedure) Sop for Operation and Calibration of Micropipette.

Sop for Operation and Calibration of Micropipette.

I. Purpose & Scope:

• The purpose of this SOP is to lay down a procedure for Operation and Calibration of Micropipette.
• This Standard operating procedure is applicable for operation and calibration of Micropipette in the Microbiology section of Quality Control Department

II. Responsibilities:

• All Quality Control and Quality Assurance personnel shall be responsible to follow and implement this SOP i.e. Operation and calibration of Micropipette:

III : Introduction and Procedural Part :

Operation and calibration of Micropipette:

• The Micropipettes are available as fixed or variable volume size.
• General purpose of Micropipettes is for sampling and dispensing accurate amounts of liquid in micro volumes.
• Micropipettes operate on the air displacement principle.
• Micropipettes are equipped with a built-in Tip Ejector, to eject the tip by pressing it down.
• The volume can be changed by rotating the ‘operating push button’ to clockwise or anticlockwise.

Aspirating Liquid :

• The liquid which is to be aspirated shall be taken from a suitable vessel.
• Attach the tip to the pipette firmly. Press the operating button to the first stop.
• Immerse the pipette tip approximately 3 mm to 5 mm into the liquid or upto suitable depth into the aspirating liquid.
• Allow the operating button to slide back slowly. Pipette will aspirate the liquid.
• Pull out the micropipette tip from liquid slowly.

Dispensing Liquid:

• Hold the tip at an angle against the inside wall of the receiving tube /well /vessel.
• Press down the operating button slowly to the first stop and wait for a second.
• Press down the control button to the second stop. This will empty the tip completely.
• Hold down the operating button and remove the pipette from the vessel by sliding its tip up to the wall of vessel.
• Allow the operating button to release back to ready position.

Calibration:

• Calibration of micropipette should be done to obtain percentage of error.
• Calibration should be performed at lower, middle and higher volume limit.
• Attach micropipette tip to micropipette firmly. Set the desired volume by rotating operating button. Aspirate the water and dispense into beaker (previously weighed), Take balance reading in mg. The Obtained weights in mg(X) shall be converted into µL using the following formula;

                                          Weight in µL ₌ Weight of water in mg (X)

Density of water (at 25°c)

• The Percentage of error can be calculated by using following formula;

              Percentage of Error (% of Error) = Volume for verification – Weight in µL X 100

Volume for verification

• Frequency: Calibration of Micropipette should be done quarterly (after every 3 months).
• Acceptance criteria: % of Error should not be more than 1.
• Record the calibration data in ‘Micropipette calibration record’, refer Annexure-I.

Handling, Care and Cleaning:

• Aspirate liquid into the pipette only when a tip is attached to its tip cone.
• While pipetting, the pipettor should be vertically straight and tip should be dipped only a few millimeters into the liquid.
• Always control the push button movements with the thumb for consistency.
• Allow aspirating liquids to attain ambient temperature, before pipetting.
• Don’t keep pipette in your hand while not working to avoid transfer of body heat.
• To clean the pipette, use ethanol and a soft cloth or lint free tissue. clean the tip cone regularly.

Annexure :

Annexure I: Micropipette Calibration Record

                                                                   Annexure I

Micropipette Calibration Record

Acceptance criteria : % of error should not be more than 1.

Done By :                                                                                               Checked By :

Date :                                                                                                      Date :