How to Use a Micropipette: SOP For Using a Micropipette

Contents

SOP For Using a Micropipette

To take small volumes with great accuracy

It is applicable to the microbiology laboratory

Microbiologist

Make sure that the pipette is in good condition.
Check the micropipette by pre-wet the tips 2-3 times.
After checking the pipette, adjust the desired volume which you want to take by rotating the volume setting ring of pipette.
Set the representative tip for the Pipette.
Press and hold the plunger of the pipette at the first stop.
Place the pipette tip into the liquid which you want to take. Make sure that the pipette is insert in the liquid in the erect position.
Slowly release the plunger of the pipette.
Pause for a second so that no bubbles form in the tip.
Move the tip from the liquid to the delivery vessel. Place the tip against the wall of the delivery vessel.
Press the plunger to the second stop. Make sure that the pipette tip is inserted in erect position.
Pause for 2 seconds and then release the plunger.
Eject the tip into waste container by ejector

There are some precautions that need to remain in mind while using the micropipette.

The calibration of the micropipette is done by using water samples at room temperature.

Weigh the glass beaker at room temperature and tare it.
Set the desired volume and take the water sample with the micropipette at the desired volume.
Aspirate the volume and dispense it in an empty weighed glass beaker.
Weigh the beaker and repeat this 10 times
Then, take the mean of the weighs. And convert it into μL by using the formula

Volume = weight of water samples/density of water samples at 25°C

After getting the weight in μL, calculate the percentage variation of micropipette by using the formula

% Variation =(100 x Actual weight – Observed weight)/D

Accuracy (%Error) = Mean – Set Volume x 100 / Set Volume

Precision (% CV) =Standard Deviation × 100 / Mean