How to check the calibration of your pipets.
Using your lab balance you can get a fair idea if your pipette is grossly out of calibration.
You will need the following items:
o Distilled or deionized water
oA container to pipet from.
o A container to pipet into, such as a scintillation vial.
o A balance with at least 0.1 mg resolution if checking 30 ul and greater pipets, or 0.01 mg for 30 ul and below.
Place the vial on your balance and tare the balance.
Set your pipette to its minimum volume and prewet the tip by pipeting 2 or 3 times.
Tare the balance and pipette into the vial.
Take several readings, tare between each, and write down the results.
Now repeat the procedure with your pipette set to its maximum volume, again writing down your results.
Take your readings and multiply by 1.003 (this is an approximate correction to convert the weight of the water to the corresponding volume at typical lab conditions. Approx. volume = weight / density of water).
Now compare your results to the manufacturer's specifications.