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Serial Dilution- Definition, Method, Calculator, Process, Makes use of


Serial dilution, because the title suggests, is a sequence of sequential dilutions which can be carried out to transform a dense resolution right into a extra usable focus.

  • In easy phrases, serial dilution is the method of stepwise dilution of an answer with an related dilution issue.
  • In biology, serial dilution is commonly related to lowering the focus of cells in a tradition to simplify the operation.

Picture Supply: Chromoscience

Aims of Serial Dilution

  • The target of the serial dilution methodology is to estimate the focus (variety of organisms, micro organism, viruses, or colonies) of an unknown pattern by the enumeration of the variety of colonies cultured from serial dilutions of the pattern.
  • In serial dilution, the density of cells is lowered in every step in order that it’s simpler to calculate the focus of the cells within the unique resolution by calculating the full dilution over the complete sequence.
  • Serial dilutions are generally carried out to keep away from having to pipette very small volumes (1-10 µl) to make a dilution of an answer.
  • By diluting a pattern in a managed approach, it’s attainable to acquire incubated tradition plates with an simply countable variety of colonies (round 30–100) and calculate the variety of microbes current within the pattern.

Serial Dilution Method/Calculations

  • Serial dilution includes the method of taking a pattern and diluting it by a sequence of ordinary volumes of sterile diluent, which might both be distilled water or 0.9 % saline.
  • Then, a small measured quantity of every dilution is used to make a sequence of pour or unfold plates.
  • Relying on the estimated focus of cells/organisms in a pattern, the extent of dilution is set. For e.g., if a water pattern is taken from an especially polluted setting, the dilution issue is elevated. In distinction, for a much less contaminated pattern, a low dilution issue is likely to be adequate.
  • Serial two-fold and ten-fold dilutions are generally used to titer antibodies or put together diluted analytes within the laboratory.
  • The dilution consider a serial dilution may be decided both for a person take a look at tube or may be calculated as a complete dilution consider the complete sequence.
  • The dilution issue of every tube in a set:
dilution factor of each tube

For a ten-fold dilution, 1 ml of pattern is added to 9 ml of diluent. On this case, the dilution issue for that take a look at tube might be:

Dilution factor formula
  • After the primary tube, every tube is the dilution of the earlier dilution tube.

Now, for the full dilution issue,

  • Complete dilution issue for the second tube = dilution of first tube × dilution of the second tube.


For the primary tube, dilution issue = 10-1 (1 ml added to 9 ml)

For the second tube, dilution issue = 10-1 (1ml added to 9 ml)

Complete dilution issue = earlier dilution × dilution of subsequent tube

= complete dilution of 10-1 × 10-1 = 10-2

On-line Serial dilution calculator

AAT Bioquest, Inc. (

Merck (

Omni Calculator (

Endmemo (

Handymath (

Tocris Bioscience (

Physiology Net (

Selleck Chemical compounds (

ApexBio Expertise (

CiteAb (

Fluffy Frog (http://fluffyfrog.web/calc/)

Practical Biosciences (


Process of Serial Dilution

The next is the process for a ten-fold dilution of a pattern to a dilution issue of 10-6:

  1. The pattern/tradition is taken in a take a look at tube and 6 take a look at tubes, every with 9 ml of sterile diluents, which might both be distilled water or 0.9% saline, are taken.
  2. A sterile pipette is taken.
  3. 1 ml of correctly combined pattern/tradition is drawn into the pipette.
  4. The pattern is then added to the primary tube to make the full quantity of 10 ml. This gives an preliminary dilution of 10-1.
  5. The dilution is totally combined by emptying and filling the pipette a number of instances.
  6. The pipette tip is discarded, and a brand new pipette tip is connected to the pipette.
  7. Now, 1 ml of combination is taken from the ten-1 dilution and is emptied into the second tube. The second tube now has a complete dilution issue of 10-2.
  8. The identical course of is then repeated for the remaining tube, taking 1 ml from the earlier tube and including it to the subsequent 9 ml diluents.
  9. As six tubes are used, the ultimate dilution for the micro organism/cells might be 10-6 (1 in 1,000,000).
Procedure of Serial dilution
The process of Serial dilution.

Serial Dilution Purposes/Makes use of

Serial dilution is carried out in a variety of experimental sciences like biochemistry, pharmacology, physics, and homeopathy.

  1. Serial dilution is utilized in microbiology to estimate the focus or variety of cells/organisms in a pattern to acquire an incubated plate with an simply countable variety of colonies.
  2. In biochemistry, serial dilution is used to acquire the specified focus of reagents and chemical compounds from a better focus.
  3. In pharmaceutical laboratories, serial dilution is carried out to obtain the required focus of chemical compounds and compounds, as this methodology is more practical than particular person dilutions.
  4. In homeopathy, homeopathic dilutions are used the place a substance is diluted in distilled water or alcohol. It’s believed that dilution will increase the efficiency of the diluted substance by activating its important power.

Serial Dilution Limitation/Issues

Though serial dilution is a helpful method in laboratories, it faces some challenges. A few of that are:

  1. An error would possibly happen throughout the propagation of the pattern, and the switch inaccuracies result in much less correct and fewer exact switch. This leads to the very best dilution to have probably the most inaccuracies and the least accuracy.
  2. As a result of serial dilution is carried out in a stepwise method, it requires a extra prolonged time frame which limits the effectivity of the strategy.
  3. Serial dilution solely permits the discount of micro organism/cells however not the separation of micro organism/cells like in different methods like move cytometry.
  4. This system additionally requires extremely skilled microbiologists and consultants in aseptic methods.

Serial Dilution Examples

  • A easy instance of serial dilution carried out in our every day life is tea or espresso. In espresso, we add a certain quantity of chilly press espresso and add water over it to acquire a desired focus of espresso.
  • One other instance of serial dilution is the dilution of acids and bases in chemistry to acquire a required focus.
  • Serial dilution of tradition to find out the variety of micro organism in a given pattern by a plating method can be a necessary instance of serial dilution.


  • Fundamental Sensible Microbiology-Guide. The society of Basic Microbiology. Retrieved from
  • Avishai Ben-David, Charles E. Davidson, Estimation methodology for serial dilution experiments, Journal of Microbiological Strategies, Quantity 107, 2014, Pages 214-221, ISSN 0167-7012,
  • Cullen, J. J., & MacIntyre, H. L. (2016). On using the serial dilution tradition methodology to enumerate viable phytoplankton in pure communities of plankton subjected to ballast water remedy. Journal of utilized phycology28(1), 279–298.


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