Manipulating Small Volumes
Practice with the Micropipets
I.
Practicing with a P-20
1.
Label two empty microcentrifuge tubes A and B with a permanent ink
marker, if not already labeled.
Add the amounts of solutions I, II, III and V to tubes A and B as shown in
the table below.
2.
Solution Volume in Each Tube
Reaction Solution Solution Solution Solution Solution
Tube
I
II
III
IV
V
II.
A
4 µL
5 µL
B
6.5 µL
2.5 µL
Total in
Tube
2 µL
2 µL
3.
If necessary, spin down any solutions on the walls of the tubes (be sure to
balance your tube).
4.
Add up the total volume of liquid in Tube A. AS A CHECK OF YOUR
TECHNIQUE, set the micropipet to that volume and withdraw all of the
liquid in tube A. The contents should just fill the tip -- no air space at the
bottom of the tip; no leftover liquid in the tube. Discard liquid and tip into
waste beaker.
Practicing with a P-200
1.
Add the amounts of solutions I, II and IV to a microcentrifuge tube as
shown in the table below.
Reaction Solution Solution Solution Solution Solution
Total in Tube
Tube
I
II
III
IV
V
C
20 µL
40 µL
100 µL
2.
If necessary, spin the tube for 1-2 sec.
3.
Check the accuracy of your micropipeting technique with the P-200 as you
did in Part I.
III.
Practicing with a P-1000.
1.
Add the amounts of solutions III and V to tube D as shown in the table
below.
Reaction Solution Solution Solution Solution Solution
Total in Tube
Tube
I
II
III
IV
V
D
IV.
300 µL
550 µL
2.
Spin tube for 1-2 sec.
3.
Check the accuracy of your micropipeting technique with the P-1000 as
you did for Part I.
Another test:
Reaction Solution Solution Solution Solution Solution
Tube E
I
II
III
IV
V
Volume:
15 µL
105 µL
12 µL
38 µL
350 µL
Add the volumes of solutions I-V indicated above into tube E, using the
appropriate micropipette and check your accuracy as done previously.
V. Weigh the following volumes of water on weighing paper and record your results.
Repeat twice.
Trial 1
Trial 2
100 μL: _____________
______________
15 μL: _____________
______________
400 μL: _____________
______________