What is dilution factor?The dilution factor (or dilution ratio) is the notation used to express how much of the original stock solution is present in the total solution, after dilution. It often given as a ratio, but can also be given as an exponent, however, this calculator will only show it as a ratio. Regardless if dilution factor is a ratio or exponent, it has two forms, either describing the parts of the stock solution to the parts of the dilutant added (S:D) or the parts of the stock solution to the parts of the total solution (S:T).As the difference between these two representations is very slight, an example would help to make sure that you don't get the wrong answers and mess up your experiment! Let's say you have a 10 cm 3 aqueous solution of acyl chloride. However, this is too concentrated for your experiment, so you add 90 cm 3 of water to further dilute the solution.
In serial dilutions, you multiply the dilution factors for each step. The dilution factor or the dilution is the initial volume divided by the final volume. For example, if you add a 1 mL sample to 9 mL of diluent to get 10 mL of solution, DF=ViVf = 1mL10mL=110. Today I’m bringing you a useful dilution factor calculator to help with those quick calculations in the lab. To calculate the dilution factor, you need two things: the original volume of the solution you dilute and the final volume after diluting (or the volume you have added to dilute, in which case the final volume.
You end up with 100 cm 3 of acyl chloride. As you have 10 parts of the stock solution, and 90 parts of the dilutant, the S:D ratio is 1:9 (canceling down from 10:90). In the S:T notation the dilution factor is 1:10, you have 10 cm 3 of the stock solution that now makes up a 100 cm 3 solution.It is also worth noting that dilution factors only represent a loss of - no molecules themselves are lost, just the number of them per mL decreases. This can be useful is several experimental situations. Although dilution factor is just a handy way of thinking about dilutions, dilutions are very common, both in science and in your day to day life. If you've ever made gravy, you've done a dilution. Ever washed your hands with soap?
![Calculate Dilution Factor Calculate Dilution Factor](/uploads/1/2/4/7/124749566/273883481.jpg)
You've done a dilution. They are also useful in the lab. If you wanted to replicate experiments over a range of decreasing concentrations, you would prepare what is known as a. They're also used in practically every chemical, and most biological, experiments, as the stock solution of your chemical is often far more concentrated than you desire. Dilution factor formulaNow that we've discussed what is dilution factor, let's get down to brass tacks and talk about the dilution factor formula. But first, a brief section on how to represent the dilution factor. As we mentioned above, dilution factor is often expressed as a ratio.
![Multiply by dilution factor Multiply by dilution factor](/uploads/1/2/4/7/124749566/348250791.jpg)
The simplest formula for both types or dilution factor are as follows:. S:D = stock volume:dilutant volume.
S:T = stock volume:total volumeIf these volumes are expressed in the same units, you can cancel each side down using their, you will end up with the simplest integer expression of the dilution factor. Some of you, however, may wish to express this ratio in the form 1:X, where X = how many parts of the dilutant/total solution there are for one part of the stock solution. This may leave you with some funny (not haha funny, but oh no funny) ratios, but their formulas are:. S:D = 1:(stock volume/dilutant volume). S:T = 1:(stock volume/total volume)Due to the limitations in current technology, this is also how our calculator expresses your results. We hope you can forgive us of making you do extra work.You may also see dilution factor expressed as an exponent, such as 3 -1, 5 -3 or 10 -4.
Now, do not be frightened by this new form! The exponent merely represents the ratio of the parts of the dilutant/total to the parts of the stock. Use the order of the ratio above:. S:D = exponent:1. S:T = exponent:1Now, you may or may not know, that a number with a negative exponent is the same as putting that number as the denominator when the numerator is 1, and removing the negative sign.
Our can help you with understanding this further, but for now, lets go through those examples we set out above:. 3 -1 - 1/ 3 1:1 - 1/ 3:1 - 1:3. 5 -3 - 1/ 5 3:1 - 1/ 125:1 - 1:125. 10 -4 - 1/ 10 4:1 - 1/ 10000:1 - 1:10000. How to calculate dilution factorIf you're still asking yourself 'how to find dilution factor?' , then, we hope this section will answer all of your questions.
So, just follow the steps below if you are want to calculate dilution factor by hand:. Find any two of the following three values: volume of the stock solution (stock), volume of the dilutant (dilutant), and total volume of the solution (total). This can either be done theoretically (before your experiment) or experimentally (after your experiment). Use the two volumes to find the third. Use this equation: stock + dilutant = total.
If you know which notation you would prefer to use (S:D or S:T), then you may not need this step, but we shall include it for completeness. Decide which notation you require:. S:D = set the values of the stock and dilutant amount as a ratio - stock:dilutant. S:T = set the values of the stock and total amount as a ration - stock:total. If required, cancel down the fractions by finding the Greatest Common Factor.We have already provided an example in the, so, please check that section if you are still wondering how to find dilution factor. We will, however, tell you how to calculate the volumes you need from the dilution factor:. Choose your desired dilution factor, its notation (S:D or S:T) and one of the variables either side of the colon.
Divide the number after the colon (D or T) by the number before the colon (S). We will name this value will be known as the factor. Use the following equations depending on your choice of notation:. S:D = stock.
factor = dilutant or dilutant / factor = stock. S:T = stock. factor = total or total / factor = stockThere you have it - we hope this solves any of your issues regarding dilution factors. You can always check your results with our dilution factor calculator, or just use it in the first place. It works in either to find the dilution factor or to find the volume required to achieve a certain dilution factor, just input the fields you know into our tool!
Pages: 1 Dear allI am confused regarding the calculation of dilution factor. As far as I know, dilution factor = volume of sample/total volume and CFU = (#colony x dilution factor)/volume plated in mL. For example, if I added 1g of sample into 9mL of broth - 10^-1, and transfer 1mL from 10^-1 to second tube (9mL as well). Then this will be 10^-2. Thus, if 1000mL of sample in tube 11 plated onto the agar and I obtained 30 colonies in this plate, CFU = (30 x 10^-11)/1000mL Well, now came to my confusion partWhat if I added 1g of sample directly to 99mL of broth, what is the dilution factor here?
According to formula it will be 1/100mL or 10^-2? But 100mL is equivalent to 11 tubes of 9mL broth, so if look at this way, it will be 10^-11 instead of 10^-2? Please advice. Thank you. Celz on Tue May 6 00: said:Dear allI am confused regarding the calculation of dilution factor. As far as I know, dilution factor = volume of sample/total volume and CFU = (#colony x dilution factor)/volume plated in mL. For example, if I added 1g of sample into 9mL of broth - 10^-1, and transfer 1mL from 10^-1 to second tube (9mL as well). Then this will be 10^-2. Thus, if 1000mL of sample in tube 11 plated onto the agar and I obtained 30 colonies in this plate, CFU = (30 x 10^-11)/1000mLCorrect this far.Celz on Tue May 6 00: said:Well, now came to my confusion partWhat if I added 1g of sample directly to 99mL of broth, what is the dilution factor here? According to formula it will be 1/100mL or 10^-2?
But 100mL is equivalent to 11 tubes of 9mL broth, so if look at this way, it will be 10^-11 instead of 10^-2? Please advice. Thank you.Where you have it wrong is that in your dilution series you are taking 1/10th EACH time you dilute, so from your initial 1 g, at the next step you are taking 0.1 g to the new tube, and the next 0.01 g and the next 0.001 g and so on. Thanks for your reply. Btw, if we following the formulaCFU= (#colony x dilution factor)/volume plated in mL If I obtained 30 colonies from second dilution tube (10^-2), Thus, CFU= (30x 10^-2)/1mL= 30 x 10^-2 CFU/mL May I know is the calculation method get wrong? How come the answer is 30 x 10^-2 (0.3) instead of 30x10^2? Thanks for all the explanations. I still have one more question on itI was added 1g of sample to 99mL to make it become 10^-2, after that I transferred 1mL from this bottle to 9mL of broth, serial dilution was performed until it came to 10^-10 (8th tube). The CFU obtained was 2. HoweverWhen I added 1g of the same sample to 9mL broth (to make the initial dilution factor become 10^-1) and followed by serial dilution until 10^-10 (9th tube).
The result obtained was 8764. Both are the same dilution factor, how come the results are so big different? Thank you. Thanks for all the explanations. I still have one more question on itI was added 1g of sample to 99mL to make it become 10^-2, after that I transferred 1mL from this bottle to 9mL of broth, serial dilution was performed until it came to 10^-10 (8th tube).
The CFU obtained was 2. HoweverWhen I added 1g of the same sample to 9mL broth (to make the initial dilution factor become 10^-1) and followed by serial dilution until 10^-10 (9th tube). The result obtained was 8764. Both are the same dilution factor, how come the results are so big different? Thank you. very simple answer: you have problems with making dilutions. Making dilutions is something that many many people do wrong (or underestimate).
IN some companies new people have to 'train' on this for 1-2 weeks. Just to do it correctly.You mixed it well?
Especially when adding 1 gr to 99ml. Other reasons: the start sample was not correct (there can be a huge difference between 'samples' (the powder form) if its not mixed well. I don't know the details about your samples, but it could be a reason. Also: a CFU of 2 is too low to take into account, its not enough, you need to be between 30-100 (something like that). 2 means nothing: it can be 2, 1, 0, 4 or 5. 2 is too low Its btw better to start with 1 gram in 9ml and than dilute more. In addition to Pito's comments - If you want to do 1:100 dilutions you don't have to use 99 ml and 1 g, you can use 9.9 and 0.1 g if you want to. Note also that 1 g doesn't necessarily equate to 1 ml, solute volume could be playing a part here!!! Like Pito said, the difficulty is error - measuring 99 ml by most methods is not very accurate, for example a standard glass 100 ml measuring cylinder has an error of +/- 1 ml at STP. You could use a volumetric flask for 100 ml (+/- 0.01 ml if used properly) and weigh out 1.01 g. Similarly if you do multiple measurements of say 25 ml lots (e.g. Disposable serological pipette error +/- 3% or 0.75 ml at 25 ml) then the errors are additive 0.75 +0.75+0.75 +0.75 = +/- 3 ml. However, if you just add a single volume to a tube - then the error is a single value and there is inherently less error in measuring 10 ml than there is in 100 ml because the graduations are finer - hence the repeated dilutions are more accurate than the single larger one.