This is really dumb but i never realized how important this is until lately when my protein assay standards were looking funky. i was wondering if there were any tips people could give me on how to be good at micropipetting. i thought it was a no brainer but looks like it really is an art. i've been taught before to just submerge the pipette tip in the larger volume of solution to dispense smaller volumes like 1ul; however, it seems it is easy to double that volume from the extra sample that may be on the outside of the tip.
My current understanding is to place the tip of the pipette against the wall of the microfuge tube and expel the contents slowly and draw back. this has worked for the most part except when the liquid instead of forming a perfect bead at the tip flows backwards under my pipette tip and forms a pool. when i try to drag it off it does follow my tip for a while before it dislodges. I can't imagine all the extra volume i may have lost just observing how the sample sticks to my tip.
How can i prevent this? i want to believe as long as i am consistent with how i treat each sample it should be fine but seriously i can't help dragging circles with the tip and re-expeling the pipette to force the sample off.
Edited by azrael201, 01 February 2011 - 08:38 AM.