BACKGROUND
Techniques Lab A ext: Practice with Viscous Solutions
Background
Enzyme and DNA solutions are often thick and viscous due to high concentrations of
protein, DNA or a stabilizing agent such as glycerol. Viscous solutions require
extra care in pipetting in order to deliver accurate amounts of sample and to not
waste precious materials.
Purpose
To refine your pipetting technique, working with tiny volumes and viscous solutions.
Materials per team
| Solution A, colored glycerol solution |
rack for reaction tubes |
| P-20 micropipet and yellow tips |
container for waste |
REVIEW
| -Set pipet volume only
within the range specified for that micropipet. |
 |
| -When using a micropipet, first apply a tip. |
 |
| -Always keep a micropipet in a vertical position when there is fluid
in the tip. |
 |
| -Use your thumb to control the speed at which the plunger rises after taking up or
ejecting fluid. |
 |
TO EMPHASIZE
| -When FILLING the pipet tip, push down the plunger to the FIRST STOP and
hold it there. |
 |
| -Lower the tip just below the surface of the liquid to be sampled. Ease up on the
plunger SLOWLY so the sample is carefully drawn into the pipet tip. |
|
-Remove the pipet tip from the sample. OBSERVE the volume of sample in the tip. NOTICE
if it is a small amount, tiny amount, or teeny-weeny amount...
|
-Pick up the tube or locate waxed paper for dispensing liquid. Position the tip to
barely touch the receiving surface.
|
|
| -SLOWLY push down plunger to the FIRST STOP. THEN SLOWLY push down the plunger to
the SECOND STOP to deliver all the sample. |
 |
| -HOLD THE PLUNGER DOWN AT THE SECOND STOP WHILE moving the pipet away
from the sample. |
 |
|
|
|
AE Partners Collection Index
