Make sure you are producing accurate and reproducible results consistently with these pipetting best practices contributed by experts.

1. Take good care of your pipette. Clean regularly, removing dust and dirt on the outside as observed (you can wipe with 70% ethanol), and check for damage daily. Keep your pipette in its stand (or at least in an upright position) when not in use. Use a UV hood to sterilize if working with PCR products or other potential genomic contaminants.

2. Routinely calibrate your pipettes. Frequent checks will help weed out malfunctioning units.

3. Be careful with open tubes. Always pipette in a fashion that doesn’t cause you to hover over open tubes. You don’t want to accidentally drip on or touch an open tube. Once you’ve finished with a tube, close the cap to help you keep track of your progress and avoid this type of contamination.

4. Have multiple pipettes. Keep designated sets of pipettes for every lab station to avoid cross contamination.

5. Take care with reagents. Only keep one reagent open at a time to avoid accidentally pipetting the wrong one and minimize aerosol or particulate from entering your stock.

6. Use the right pipette for every application. For instance, don’t use an air displacement pipette for corrosives or biohazardous materials; a positive displacement pipette is a better choice for these solutions.

7. Size matters. Make sure that you use the most accurate pipette for the volume you are measuring. For example, don’t use a 1 mL pipette to measure 125 uL. Size down to a 200 uL pipette for better results. Accuracy ranges are printed on all pipettes.

8. Always use the right tips and ensure that they fit properly. Ill-fitting tips allow air to escape when drawing up and dispensing liquid. Do not re-use tips; most are designed for single use. Use barrier tips when necessary to avoid contamination of pipette. (e.g. pipetting PCR product)

9. Prewet the pipette tip to help increase accuracy. Pre-rinsing the tips (at least three times) with the liquid to be pipetted is important, especially with volatile samples.

10. Use the right pipetting mode. Standard (forward) is recommended for all aqueous samples. Reverse mode is often recommended for viscous or volatile samples.

11. Aspirating. Have a consistent pipetting rhythm for each step in the pipetting cycle. Pipette at a speed that you are comfortable with. Use consistent pressure for each sample. Pause for one second immediately after aspirating, with the pipette tip in the sample liquid. Pull the pipette straight out, avoiding the sides of the container. Check for air bubbles in the tip.

12. Dispensing. During dispensing, the tips should be slightly dragged up the receptacle wall to allow all liquid to be drawn from the tip. Consistent speed and pressure is important during dispensing. Depress to the second stop to expel all the remaining liquid. Remove the tip from the tube before releasing the plunger. Check the tip after to make sure nothing remains.

13. Viscous reagents. When dispensing viscous reagents, rinsing the tip in the solution after dispensing will yield the best results by ensuring that the mixture is homogenized and that no reagent gets left in the tip. Gently pipette up and down until cleared.

14. Immersion. Take care with tip/pipette immersion. Depth is important. If too shallow, air could be aspirated; too deep and droplets might collect on the outside of the tip. Do not let the tip/pipette touch the sides or bottom of the sample vessel. Make sure you use a long enough tip to avoid this.

15. Handling. Hot hands can heat up the barrel of a pipette. Wear gloves and make sure you hold the pipette loosely and return to its stand between uses.