How to accurately carry out the process of serial dilution

How to accurately carry out the process of serial dilution


  • Post By : Kumar Jeetendra

  • Source: Microbioz India

  • Date: 30 Mar,2023

In serial dilution, a solute is diluted from a high concentration to a low concentration in a series of solutions. In the fields of microbiology and biochemistry, this technique is frequently employed to reduce sample concentrations to levels at which individual cells or molecules can be isolated and studied.

What is serial dilution:

In the lab, one of the most frequent methods is called “serial dilution,” and its purpose is to create a variety of dilutions from a single stock solution.

In this step of the process, you will measure out a fixed amount of the starting solution and pour it into a fresh container that already contains a fixed amount of the diluent (usually water or buffer solution). After the resultant solution has been carefully mixed to ensure that it is homogenous, a portion of this solution is taken out and transferred to the following container, which already has the same volume of diluent as the previous one. This procedure is carried out a number of times in order to produce a succession of dilutions with progressively lower concentrations.

For instance, if you have a stock solution of 10 mM and you want to prepare a series of 10-fold dilutions, you could take 1 mL of the stock solution and combine it with 9 mL of diluent to produce a solution that has a concentration of 1 mM. This would be the first step in the preparation of the dilutions. After that, take 1 millilitre of the solution that is 1 millimolar and mix it with 9 millilitres of diluent to make a solution that is 0.1 millimolar, and so on.

How to do serial dilution:

Here are some tips to help you perform serial dilution effectively:

  1. To prevent contamination at each stage of the dilution process, use a pipette that has been thoroughly cleaned and is sterile.
  2. To prevent any misunderstandings, ensure that each well or tube is labelled with the appropriate dilution factor.
  3. Put your dilution series together in an order that makes sense, such as going from the highest concentration to the lowest concentration or vice versa.
  4. Ensure that the solution is well mixed after each stage of dilution to confirm that the correct concentration has been reached.
  5. Ensure that the tip of the pipette corresponds to the volume that is being transferred. For example, when transferring 1 ml of solution, use a pipette tip that is rated for 1 ml.
  6. To avoid the risk of cross-contamination, you should avoid touching the edges of the tubes or wells when you are transferring solutions.
  7. To confirm that the diluent you are using does not affect the results of your experiment, use a control that is blank.
  8. If you are working with a stock solution that is extremely concentrated, it is possible that you will need to undertake numerous stages of dilution in order to acquire the dilution factor that you require.
  9. As a last step, make certain that you document all of the stages of the serial dilution in your lab notebook. This should include the volumes as well as the concentrations of each successive dilution.

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