In this video we will introduce you to Pipetman pipettes and how to perform forward and reverse pipetting using these pipettes.
The three types of Pipetman we will introduce in this video are P1000, P200, and P20.
The number denotes the maximum volume transferred by the Pipetman in microliter.
You should never go over the limit as this will damage the Pipetman.
The range of a P1000 is between 200 microliters to 1000 microliters,
represented by 020 to 100 on the dial.
For any volume lower than 200 microliters,
you need to go to the next available Pipetman, which is the P200.
For a P200, the range is between 20 microliters to 200 microliters,
denoted by 020 to 200 on the dial.
For P20, the dial at “200” indicates 20.0 microliters and “020” indicates 2.0 microliters.
There are different pipette tips available for different Pipetman.
These ones are used for P1000 while these are used for P200 and P20.
When operating a Pipetman, first turn the thumbwheel to change the volume of delivery.
Please note that you should never exceed the limits of each Pipetman or you will damage it.
Install a pipette tip by pressing the Pipetman to a tip in the box.
You should never attempt to use a Pipetman without a pipette tip for liquid delivery.
There are two stops when operating a Pipetman.
To draw up the liquid, press the push button to the first stop,
insert the pipette tip halfway into the liquid,
then slowly release the push button to draw liquid into the tip.
To dispense the liquid, press on the push button to release most of the liquid,
then further apply pressure on the push button to a second stop to eject the last drop for accurate volume transfer.
If you need to change a pipette tip, you can eject the tip by pressing the tip ejector button.
You should never leave a Pipetman with liquid in the tip on the bench,
the liquid will be released into the shaft and affect the function of the Pipetman.
Always eject the pipette tip before putting it down.
To avoid error of pipetting, never draw at the surface of the liquid nor the very bottom.
Reverse pipetting can also be performed using the Pipetman pipette.
Reverse pipetting is a great alternative method to forward pipetting
when bubble formation is an issue such as in spectrophotometric assays.
Now we will demonstrate how to dispense liquid into 96-well plate using the reverse pipetting technique.
As mentioned before, Pipetman pipettes have 2 stops.
To reverse pipette, push the push button to the first stop and push a bit beyond the first stop but not all the way to the second stop.
Then insert the tip into the liquid and slowly release the push button to draw up the liquid.
Now dispense your liquid until the first stop.
Leave the remaining liquid in the tip to repeat the process
or discard the remaining liquid along with the tip into the garbage bin.
Here is a side by side comparison of how the 96-well microplate looks with reverse pipetting and forwards pipetting.
As can be seen, forward pipetting is more likely to create bubbles if the liquid is not carefully expelled.
Looking at the results obtained from reading the 96 well plates,
we can see that reverse pipetting allowed for more accurate absorbance readings
as demonstrated by the greater resulting R squared when compared to the forward pipetting standard curve.
Thank you for watching.