Concept: Micropipettes work by an air displacement mechanism
- Set the P200 to deliver 200 μL. Be careful not to overshoot, which could damage the pipette piston.
- Grip the pipette by wrapping your fingers around the barrel. Use your thumb to depress the plunger to its first stop.
- Next press the plunger to the second stop. Compare the distance that the plunger moved dur- ing the first and second strokes.
- Set the P200 to deliver 20 μL and depress the plunger to its first stop. Compare the distance that the plunger moved when the P200 was set to 200 or 20 μL.
- Depress the plunger to the second stop. How does the distance between the first and second stops compare for 200 and 20 μL?
- Set the P20 to deliver 20 μL. Depress the plunger to the first stop. Compare the distance to the first stop when a P20 and P200 are set to deliver 20 μL.
Concept: The filling and dispensing strokes are different.
- Place a tip on the shaft of the P200.
- Set the P200 to deliver 50 μL.
- Draw up 50 μL of 0.05% BPB solution into the pipet.
- Dispense the BPB into a microcentrifuge tube down to the first stop, holding the tip against the wall of the tube. Note whether all of the dye has been expelled. Push the plunger down to the second stop to release any remaining BPB.