5.2: Lab Procedures- How to operate a Pipettor
Getting to Know Your Pipette
A pipet is a commonly used laboratory piece of equipment used to transfer a measured volume of liquid. A mechanical pipettor, shown in Fig. 1, can come in range of volumes it can transfer. Careful attention to its use, operation, and practice is needed to be proficient.
1. Find the following parts on your pipette: Fig. 1 Pipettor
- Volume adjustment dial
- Tip ejector button
- Plunger button
- Stainless steel micrometer
- Digital volume indicator
- Stainless steel ejector arm (removable)
- Plastic shaft
- Disposable yellow or blue tip
2. Practice holding your pipette correctly, placing a tip on our pipette, and ejected the tip. Do this at least three times.
3. The total volume a pipette can hold is stated on the top of the plunger. It is listed as "μl" or microliter volumes. We will be working with the following three volume pipettes:
- P-20: 0.02 μl – 20 μl
- P-200: 20 μl – 200 μl
- P-1000: 200 μl – 1000 μl
4. Based on the volume pipette you have the numbers in the digital display have a different meaning.
5. Rotate the volume adjustment knob until the digital indicator reaches the desired volume, then place a disposable tip on the shaft of the pipette (practice all three volumes min, int, max)
6. Press down on the plunger to the First Stop. (You will be able to push past this point, but there is enough resistance to stop the movement if you try to be aware of it.)
7. Hold the pipette vertically and immerse the disposable tip into the sample. Use the colored water and the microcentrifuge tubes provided to you.
8. Allow the plunger button to return slowly to its original position. Do not allow the button to snap up.
9. To dispense the sample: place the tip against the side wall of the receiving tube and push the plunger down to the first stop. Wait 2-3 seconds, then depress the plunger to the second stop in order to expel any residual sample in the tip.
10. While the plunger is still pushed down, remove the pipette from the tube and allow the plunger to slowly return to its original position.
11. Practice.
Warning
- Never rotate the volume adjustment knob past the upper or lower range of the pipetman.
- Never lay the pipetman down on its side or hold it horizontally when it contains liquid.
- Never immerse the shaft of the pipetman into the fluid.
Watch this video 1: Micropipetting
Watch Video 1 : how to use a micropipettor URL: https://youtu.be/NgosWmRjjAo (5:02)