Question

Jackie wants to transfer 380 µL from beaker A to beaker B. She picks a blue p1000 micropipette and sets it to the correct amount. Then she puts on a yellow pipette tip and starts the transfer. She pushes the plunger down to the first stop and places the pipette tip underneath the liquid line and slowly draws up the liquid. Next, she places the tip in beaker B and pushes the plunger to the first stop, watching the liquid go into the beaker, and then she releases the plunger. Jackie then decides she wants to put the liquid in a different container, beaker C. She uses the same tip as before and repeats the steps she followed above.

What three things did Jackie do wrong? Explain why these three things were wrong and how you would fix the issues. (6 pts)

Answer 1

ANSWER- STEPS WHICH ARE TO BE FOLLOWED FOR CORRECT MICROPIPETTING-

1. Take the pipette and set the correct volume in the tip.
2. Attach the tip to the micropipette by putting shaft in the tip. Donot touch the tip ends with bare hands to avoid contamination.
3. Press the plunger to the first stop.
4. Then put the tip at the vertical angle below the surface of solution to avoid the error.
5. Then release the plunger slowly so that liquid can enter into the tip and wait for about 1-2 seconds so that full or required liquid be filled in the tip.
6. Then hold the tip in the second beaker at the vertical angle touching the sides of the wall of the container.
7. And again press the plunger to first stop to release the contents and after 1-2 second to second stop to completely dispense the contents
8. Remove the tip with the help of tip ejector.
9. Then follow the same procedure with another tip.

In the question, Jackie do the micropipetting with some mistakes. The mistakes and the reason why they are mistakes and how can they be rectified which jackie made while pipetting are as follows-

• Mistake-  Placing of pipette tip underneath the liquid line while drawing up the liquid.
• Reason why this is wrong- Placing of tip underneath the liquid line causes contamination and there is chance of getting liquid drops attached to the tip which will change the volume of the required liquid.
• Fixing of issue- Place the tip just below the liquid at the vertical angle to draw the liquid to avoid contamination and to draw correct amount of liquid.

• Mistake- Pushing of plunger only to first stop while releasing the liquid in beaker B.
• Reason why this is wrong- To dispense the liquid, plunger will be pressed to first stop to release the contents and after 1-2 second to second stop to completely dispense the contents.
• Fixing of issue- Take the another tip and fill it by following the steps as described above nd release the liquid of the tip by pressing the plunger to first stop to release the liquid and after 1-2 second to second stop to completely dispense the liquid.

• Mistake- Usage of same tip to put the liquid in container C.
• Reason why this is wrong- The tip which is used in beaker B touched to the beaker which may lead to contamination.
• Fixing of issue- Replace the tip or use another tip to transfer the liquid in beaker C.

These are the three mistakes which are made by jackie while micropipetting.