Here are some problems, ranging from easy to a bit hard. If I don't know the actual amount of original brew, I also won't know how much caffeine there was total. If the dilution factor is in decimal form,įinally, notice that I'm telling you the total number of caffeine molecules ONE CUP of the original brew.If the dilution factor is in the form of a fraction,.Dilution factor is used in the calculation of Colony forming units/ml or cfu/ml of original. This method is called multiplying by the inverse (of the dilution factor). We use serial dilution to dilute a concentrated sample. So, when we count the caffeine molecules in a cup of wimpy coffee, we know we got 1/50th of what was in a cup of the original brew - or in other words, there was 50 times as much in a cup of the original. In the case of wimpy coffee, it was 1/50, or 0.02. Calculate the Number of Cells in Original Sample. After that, a small amount of sample from each dilution is used to prepare a series of pour or spread plates. In serial dilution, the selected sample is diluted through a set of standard volumes of sterile diluents, such as be distilled water or 0.9 saline. All we need to know is what the overall dilution factor was. Formula/calculations for serial dilution technique. The simple formula of C1V1 C2V2 is a lifesaver for those who are wanting to do dilutions.
![how to do dilution series calculations how to do dilution series calculations](https://thebumblingbiochemist.com/wp-content/uploads/2019/08/serialdilutions2-100.jpg)
"Scaling up" means starting from a sample and figuring out how many were in the original brew, or stock, or whatever was originally there.įor example, we can start with a cup of wimpy coffee and figure out how much caffeine was in the original brew.
![how to do dilution series calculations how to do dilution series calculations](https://i.imgur.com/yt7A1n7.png)
How do we account for that? By scaling up. You need to find out your dilution factor for calculating the cell density of the original sample from the density of the diluted sample youve counted. But by definition, we're counting only a fraction of what was originally there.
How to do dilution series calculations how to#
So far we've figured out how to make a dilution, which we can then plate and count.