Q&A for How to Do Pipette Calibration

Pipette calibration is important to ensure the accuracy of what you're measuring. Inaccurate measurements could have adverse effects on experimental data.

If the distilled water you used was 24 degrees Celsius at atmospheric pressure, your Z value would be 1.0038 µg/mg. Multiply these two values together (w*Z) to obtain your V value, or volume of water dispersed. This V value you just calculated is your Vavg. Divide Vavg/Vo (the amount you're theoretically pipetting, in this case it would be 1mL) and multiply this number by 100. That will be your accuracy percentage. Any answer between 99-101% is properly calibrated.

Fast-release pipette pumps are made for pipettes that are calibrated to the tip but retain the final drop. They are usually calibrated professionally by the company that manufactures the pump.

The reference standard is ISO8655. This is a verification of your pipette readings, but, if you require a valid certificate, the calibration should be done by an accredited calibration laboratory IEC/ISO 17025.

You're confusing the human concept of uncertainty with the scientific concept. For a pipette, uncertainty isn't expressed in terms of conceptual sources of uncertainty. It's expressed in mathematical terms based on the standard deviation of a set of measurements.

The formula for calculating a z-score is z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation. As the formula shows, the z-score is simply the raw score minus the population mean, divided by the population standard deviation.