1.bring 5ml of bromophenol blue to your work station. obtain a P20 Pipetman and
ID: 743615 • Letter: 1
Question
1.bring 5ml of bromophenol blue to your work station. obtain a P20 Pipetman and record below the digits you see in the window on the side. What volume is the micropipette set to deliver?2. Set your P 20 to deliver 2ml . Using the tiny bead of dye you just placed onto the Paraflim, transfer dye to a second piece of Parafilm using 2ml increments- this requires pipetting a total of 5 times.
As you draw up the last bit of dye the 5th time around, look closely at the fluid in the pipette tip- does it contain 2 ml? I f not, speculate on where you may have lost some of the dye's volume?
Explanation / Answer
Your question is a little confusing because micropipettes usually do not pipette ml (milli-liter) amounts. Rather they dispense ul (micruo-liter) amounts. So to answer your question I am going to assume you mean ul. If I'm incorrectly assuming this, you can ignore my answer. :P So P20s usually dispense 2ul to 20ul. So when you read the window, the amount should read somewhere within that range. The window should contain two or three digits. The first is the tenth place holder, the second is the one place holder, and the third (if it has it) is the first decimal point. So if it reads 185 it would be 18.5ul or if it read 047 that would be 4.7ul. So hopefully that helps answer the first question. As for the second question, it is likely that on the last draw to transfer the liquid was not a full 2ul. This demonstrates that there is a certain amount of error in pipetting. No matter how precise your P20 is every time you pipette the amount, your error gets larger and larger. Another reason that there seems to be less of the dye is because usually some amount of liquid remains within the pipette tip instead of being completely dispensed out. I hope this was helpful and at least gets you on the right track! Good luck!
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