Operation and calibration of micropipette

Operation and calibration of micropipette

1.0       OBJECTIVE

To lay down a standard procedure for Operation and calibration of micro pipette

2.0       SCOPE

This Standard Operating Procedure is applicable to Microbiology laboratory.


            Microbiologist shall be responsible to follow the procedure mention in this SOP.


Department Head & QA Head shall be accountable for effective implementation and compliance of

this SOP.


Format for calibration record of micropipette                                                  – Attachment-I

6.0       PROCEDURE

6.1           Preliminary check

6.1.1        The micropipette should be checked at the beginning of each day for dust and dirt on the surface of

the  pipette. If found unclean then clean with soft cloth duster.

6.1.2        Check visually that tip con of the pipette is not wet also check that there is no residue on tip con if

residue is observed or the tip con of the pipette is wet then use 70% I.P.A. for cleaning.

6.2          Operation

6.2.1       Volume setting    Volume can be changed continuously by rotating the setting ring.

6.2.2       Pipette Tips

6.2.1       The pipette can be sued only when a pipette tip is attached into which the liquid is aspirated.

6.3          Aspirating liquid

6.3.1       The liquid which is to be aspirated is taken from a suitable vessel.

6.3.2       Attach the tip to the pipette firmly.

6.3.3       Immerse the pipette tip approximately 3-5 mm or suitable depth into the liquid.

6.3.4       Allow the setting button to slide back slowly.

6.3.5       Pull the micropipette tip out of the liquid slowly.

6.4          Dispensing Liquid

6.4.1       Hold the tip at an angle against the inside wall of the tube/vial/bottle/suitable vessel.

6.4.2       Press down the setting button slowly to the first stop and wait until the liquid stops flowing.

6.4.3       Press down the setting button to the second stroke until the tip is completely empty.

6.4.4       Hold down the setting button and pull the tip up the inner wall of the tube.

6.4.5       Allow the setting button to slide back slowly.

6.5          Calibration

6.5.1       Calibration of micropipette should be done every month ± 15 days with weight variation.

6.5.2       Different set of volumes should be taken and linearity should be performed.

6.5.3       Attach micropipette tip to micropipette. The desired volume is set and water shall be aspirated.

6.5.4       Dispensed into dry beaker and weighed repeated for 10 times.

6.5.5       The mean of the weights are converted into µl using the following formula:

Volume =    weight of water sample

Density of water (at 25⁰C)

6.5.6       The percentage variation can be calculated by using following formula

Percentage variation =  Actual weight – Observed weight x100

Actual weight

6.5.7       Perform the calibration by using set volumes.

6.5.8       Maintain the observation in format.

6.6          Calibration Frequency

6.6.1       Calibration of micropipette should be done every month ± 15 days.

6.7          Handling, Care and maintenance

6.7.1       Do not lay down the pipette when a filled micropipette tip is attached.

6.7.2       Avoid difference in temperature between micropipette and micropipette tips as well as the liquid as

this may lead to incorrect volumes being dispensed.

6.7.3       Do not allow any liquid to enter into the pipette.

6.7.4       Do not clean the pipette with acetone or aggressive solution.

7.0       REFERENCES



SOP: Standard operating procedure

IPA : Isopropyl Alcohol

QA  : Quality Assurance

QC  : Quality Control


Quality Assurance Department

Quality Control Department


Version Number Effective Date Reason for Revision




Date Volume of water (ml) % variation Done by Checked by &


1 ml 1 ml 1 ml 1 ml 1 ml 1 ml 1 ml 1 ml 1 ml 1 ml


Percentage variationActual weight – Observed weight x100

Actual weight














Microbiology Labs Documents