The following animation demonstrates two steps in a serial dilution process producing a 1:100 dilution.
Note that the pipette should be discarded after each step and replaced with a fresh pipette.
The following gives the steps you would follow if you were to carry out successive 1/10 dilutions, 5 times.
Consider the amount required, for this example 9 mL.
Set up seven clean containers that hold about 20 mL as you will need to leave some room for mixing.
Carefully label each container with the concentration and name of the reagent.
Leaving the first container empty carefully pipette 9 mL of the diluent into each of the remaining five containers.
Carefully pipette 10 mL of the solution to be diluted into the first container.
Using a 1 mL pipette carefully transfer 1 mL of the starting solution into the second container.
Discard the pipette and using a fresh pipette, mix the contents in the second container by pipetting up and down ten times. You now have a solution that is 1/10 the strength of the starting solution in the second container.
Using the same pipette carefully transfer 1 mL from the second container to the third container and repeat step 7. You now have a 1/100 dilution of the starting solution in the third container.
Repeat steps 7 and 8 until you have finished the dilution series.
Two other considerations for making a serial dilution are:
Depending on circumstances you do not necessarily have to set up the first container containing the undiluted material
The last container will contain 10 mL. Usually this is not a problem as more reagent is made up than required. If it is a problem, simply remove exactly 1 mL of the final dilution and discard it according to the appropriate laboratory procedures.
