Training Tips Exercise
1. Display proper pipetting technique.
2. Correctly identify which pipette is appropriate for different volumes.
3. Accurately pipette μl volumes of liquid.
Exercise: Details of the exercise may vary depending upon the number of students and lab infrastructure available. (It is important to have accurately calibrated pipettes to perform this exercise.)
1. After reviewing Tips for Accurate Pipetting, obtain a set of Training Tips, pipettes, 1.5 ml tubes, and 20 ml H2O.
2. Set the P1000 to 1000 μl and firmly insert the P1000 tip marked at 1000 μl. Depress the plunger and lower the pipette
such that 3–4 mm of the tip is submerged. Slowly release the plunger, drawing the H2O into the pipette. If performed
correctly, the H2O will reach but not go past the marked line. Depress the plunger to dispense the H2O into the 1.5 ml
tube. (Do not have someone else hold the 1.5 ml tube for you. Either hold the tube yourself or use a tube rack.)
3. Using the P1000 with the 1000 μl marked tip, remove the H2O from the 1.5 ml tube and dispense back into the 20 ml of
H2O. (All of the H2O should be removed from the 1.5 ml tube and expelled from the tip.)
4. Repeat steps 2 and 3 with the other P1000 Training Tips, taking note of the changes in volumes between tips. (Make sure
to replace the Training Tips in the correct slots in the box.)
5. Repeat steps 2 and 3 with the P200, P20, and P10, using the appropriate Training Tips.
6. Using Training Tips, pipette 1 μl of H2O into a 1.5 ml tube. In a separate tube, using standard tips, pipette 1 μl of H2O
into a different 1.5 ml tube. Compare the volumes of liquids in the tubes.
7. Repeat step 6 with all P10 and P20 training tips.
Assessment: Using a non-labeled pipette tip, pipette 10 μl, 100 μl, 200 μl, or 1000 μl of H2O into clean 1.5 ml tubes. Weigh
these tubes using an analytical balance to determine how accurately you have pipetted. Continue until you can consistently
pipette these volumes accurately.
1. Which pipette should be used to most accurately pipette 1 μl, 10 μl, 100 μl, and 1000 μl.
2. True/False: When pipetting liquid, you should release the plunger quickly to draw up liquid.
3. Multiple choice: When pipetting you should
A. submerge the tip 3–4 mm.
B. press the tip firmly into the pipette.
C. hold the pipette vertically when dispensing liquid.
D. all of the above.