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Micropipette

During the semester you will make use of Pipetman® micropipettors.  When used properly, these units deliver very accurate volumes (errors less than 1%) and they are amazingly fast.  However, please recognize that micropipettors will give erroneous volumes when in the hands of someone who is careless or not operating them correctly.  Some important suggestions/comments for the micropipettor user:

  1. The working range for a micropipettor is generally from the upper value given (here 1000 mL or 200 mL) down to 1/10th of that volume. Do not go outside this range.  Micropipettors are more accurate at the upper volume and less accurate at the lower volume.  Thus it is better to pipette 200 mL with a P200 than a P1000.
  2. Dial the micropipettor to the volume desired and firmly put on a tip. Push the plunger down to the first stop and place the tip below the surface of the liquid a bit. Slowly let the plunger come up (i.e., buffer its movement with your thumb). Place the tip into the receptacle where you want to dispense the liquid.  Push the plunger down to the first stop and then to the second stop to expel the final amount.  To remove the tip, push all the way down.
  3. Some don’ts:
    • Don’t have the tip too close to the surface of the water or else you’ll draw up air rather than liquid (creating the wrong volume).
    • Don’t bring liquid up into the tip at such a fast rate that liquid gets into the micropipettor itself. This will damage the micropipettor.
    • Don’t pipette strong acids/bases or organic solvents with a micropipettor.
    • Don’t leave the micropipettor close to the edge of a bench where it can be knocked off and fall on the floor.
    • Don’t invert the micropipettor with liquid in it (the liquid will enter the pipettor) or lay the pipettor down with liquid in the tip. Always keep the pipettor vertical.
      micropipette

      micropipette

       

    • This webpage gives lots of helpful information on micropipettes.
    • Here is a video showing the proper use of a micropipette:

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