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2. Cell Dilutions

Cell Calculations 2 — Cell Dilutions

 
A common task when setting up cell culture experiments is to dilute a (stock) liquid culture containing a known concentration of cells to a lower concentration.
Calculate the volume of stock culture that must be taken and the volume of diluting medium that must be added to accomplish this for the dilutions specified in the questions.

Vol. cells:         ml  
Vol. medium:    ml  
 
The following logic may be helpful:
  • You are diluting a stock solution.
  • The extent of the dilution (as a fraction) is the final concentration divided by the stock concentration.
  • The volume of added stock divided by the final volume needs to be the same as this.
  • The volume of stock cells required is therefore:
    final volume x (final concentration / stock concentration)
  • The volume of medium is the final volume minus the volume of cells added
You should do these calculations without a calculator, i.e. in your head or on a scrap of paper. The arithmetic is easy, and you can therefore concentrate on ensuring that the order of magnitude of your answer is reasonable.