A pipette is only as good as the user and the calibration checks that are carried out routinely to check for accuracy and precision. You will receive your new pipette with a calibration certificate, but this will need to be verified for continual use and the pipette kept in tip top condition if results are to be meaningful.
It is recommended to put water and pipettes at least 2 hours in the calibration room to reach an equilibrium with the room conditions. Z-factor is used to convert mass into volume according to temperature and pressure. ISO 8655 states that the RH must be greater than 50%.
You will receive your new pipette with a calibration certificate, but this will need to be verified for continual use and the pipette kept in tip top condition if results are to be meaningful.
Inexperienced pipette users can cause substantial variations in the results obtained so this factor has to be taken into account. A steady rhythm is important with tip depth, speed and smoothness all being variables that need to be controlled.
Pipette calibration is necessary to prevent inaccuracies in order to attain better results, performance, and longevity of the pipette itself.
Temperature. Temperature has many effects on pipetting accuracy. The factor that has the greatest effect is the temperature difference between the delivery device and the liquid. The air gap (dead air volume) between the liquid surface and the piston experiences thermal expansion effects unique to the case.
Pre-wet the pipette tip. Aspirate and fully expel an amount of the liquid at least three times before aspirating for delivery. ... Examine the pipette tip for droplets. ... Pause consistently. ... Minimize handling of pipette and tip. ... Use the correct pipette tip.
The calibration of pipette is carried out by gravimetric method. When determining the volume of water, the accuracy of measurements is effected by ambient temperature, atmospheric pressure and relative humidity. These factors are usually combined to give the Z factor, used in calculation of volume of water.
5 Tips to Improve Your Pipetting AccuracyPre-rinse your new pipette tips before aspirating a sample for delivery. ... Ensure the tips immersion depth is correct. ... Ensure the micropipette is upright during pipetting. ... Apply consistent plunger pressure and speed. ... Good micropipette.
The most common way to check your pipette accuracy is by weighing water. The density of water is 1 g/mL. This means that every microliter (µL) should weigh 0.001 g. In other words, if your pipette is accurate, the amount of water you dispense will equal the amount the water weighs.
2:313:50Pipette Calibration - YouTubeYouTubeStart of suggested clipEnd of suggested clipHold it vertically when aspirating liquid and to position it at a 45 degree angle when dispensingMoreHold it vertically when aspirating liquid and to position it at a 45 degree angle when dispensing into a vessel on a balance. Pipettes can often be adjusted to correct for accuracy.
Practice a smooth and slow motion.Pre-wet the pipette tip.Hold the pipette vertically when drawing in liquid and at a 45-degree angle when dispensing.Immerse the tip slightly into the liquid during aspiration.Touch off the pipette on the sidewall of the container.
The most important factor in pipetting accuracy is the liquid temperature. The figure below shows the change in volume when the liquid has a different temperature than the pipette and air. If the temperature of the liquid, pipette and air is the same, the accuracy is not significantly affected.
The Importance of a Well-Calibrated Pipette Any discrepancy in volumes dispensed may affect the outcomes and reproducibility of an experiment such as qPCR results. It is, therefore, necessary to check pipette calibration every few months to ensure accuracy by dispensing the right volumes.
Calibration of pipettes is of great importance for accurate and precise pipetting results. Furthermore, also the ambient conditions such as air pressure, humidity, temperature and even the altitude affect every pipetting event.
every 3 to 6 monthsThe Clinical and Laboratory Standards Institute (CSLI) recommends that pipettes (single and multi-channel) and automated liquid handlers be calibrated every 3 to 6 months. A minimum of two volumes must be tested (nominal and lowest setting) with ten replicates at each volume.