Chloe Evetts (8990-4674)
May 15, 2013
The purpose of this experiment is to learn about pipetting and experimental
design. By diluting a sample, we will learn proper pipetting technique, as well as
how to properly dilute a sample.
By being able to properly use a pipette, we believe that a multitude of
experiments can be performed, including the dilution of a sample.
1. Take 1 8-well ELISA test strip (per student)
2. Label your strip on the side you start with your seat number (on the tab)
3. Use the P200 pipette, attach a white tip, fill well 1-8 with 90 μl H2O
4. Use the P20 pipette, attach a white tip and transfer 10 μl crystal violet
(from your Gram stain kit) into well 1 and 10 μl crystal violet into well 2.
5. To perform your 1:100 dilutions, use a P20 pipette attach a white tip and
transfer10 μl from well 1 into well 3 - mix, repeat and transfer 10 μl from
well 2 to well 4 – mix after each transfer
6. To perform your 1:1000 dilution Pipette 10 μl from well 3 and add it to well
5 – mix, repeat and transfer 10 μl from well 4 to well 6 – mix after each
7. Leave well 7 and 8 with water only (negative control)
Give your strip to the TA and get your optical density (OD 600 reading. We will
determine the OD with a spectrophotometer. Your TA may ask you to graph
the data from your class to determine the quality of your pipetting and
graphing skills. Results:
Positive control: pure crystal violet
Negative control: pure wa