APPENDIX 4.a
USING THE PIPET
|
A
pipet is designed to deliver a specific volume of a liquid. Three kinds of pipets are commonly used: ·
·
·
Note: Pipets marked TD (to deliver) do not
require blow-out. Pipets marked TC
(to contain) require blow-out. |
|
|||
|
To pipet a liquid, keep the index finger of
your dominant hand near the mouth of the pipet. Place the pipet tip into the
liquid container. Do not let the tip
touch the bottom or sides of the container.
|
|
|||
|
Using your other hand, squeeze the rubber bulb and place it over the mouth of the pipet. NEVER USE YOUR MOUTH TO DRAW LIQUID INTO THE
PIPET! |
|
|||
|
Release the bulb slowly in order to draw a
specific volume of the liquid into the pipet. The liquid level should be about 1-2cm above the calibration
mark. For large volume pipets, you
may need to repeatedly use the bulb to draw enough liquid. DO NOT LET THE LIQUID ENTER THE BULB. THIS MAY CONTAMINATE THE LIQUID AND PREVENT THE BULB FROM
OPERATING PROPERLY. |
|
|||
|
Quickly remove the bulb and simultaneously
place your index finger tightly over the mouth of the pipet to prevent any
liquid from escaping. Now slightly
move your finger in order to release the liquid until the meniscus is even
with the calibration mark. |
|
|||
|
Place the pipet, with your finger still on the
mouth, over the container to which you will transfer the liquid. Release your finger and let the liquid
drain completely out of the pipet. If
some of the liquid remains in the pipet tip, do not blow into the pipet to
force the liquid out (for TD pipets).
The pipet is calibrated to deliver an accurate volume in spite of some
liquid remaining in the tip. |
Note: Some Liquid Remains
in the Tip
|