The key of repeated accuracy in pipetting is consistent technique. Consistent speed and smoothness is necessary during pipetting. Avoid sudden motions when drawing or dispensing liquid.
1. Check to ensure that the pipette tip is fitted properly on the end of the pipette and seated with adequate pressure.
2. Change pipette tips between adding each sample or reagent.
3. Do not pipette a lower volume than the manufacturer’s suggestion. This will decrease the accuracy and reproducibility.
4. Some liquids will have a tendency to cling to the inside or outside surfaces of the pipette tips. Pre-rinse the pipette tip with the sample or reagent to avoid variations in the volumes drawn or dispensed caused by this surface tension. This will improve accuracy.
5. If the reagent to be pipetted is viscous, wait a moment after drawing the liquid to allow the volume to reach equilibrium before removing the pipette tip from the reservoir.
6. If air bubble appears in the tip while drawing the liquid, dispense the liquid back into the container and re-pipette the liquid at a slower rate. If the air bubble appears a second time, discard the pipette tip and replace with a new tip.
7. Use separate reservoirs for each reagent.