Hi guys,

I have a sample that is diluted 1:5 for plating.
How do I make 1:10 dilution from 1:5 dilution?

Thank you for your help. It's been a long time I haven't done this.


Thanks

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Take 50% of 1:5 dilute sample and add 50% of media/buffer to it, that makes it 1:10 dilution . its like double dilution.

Radhu

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Radhu is right.
Don´t worry, it´s easy when you get used to do it.

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"Use it or lose it"

So true are those words. I have much to say about forgetting how to do maths. So take this as a good dressing down!

Anyway

1:5 can be though as 1/5. As it means the 1:5 dilution has 1/5 the number of cells for the same volume as the original culture. This can be done by either keeping the volume the same and adding 1/5 the cells of the original culture. Or keeping the number of cells constant and increasing the volume of cells 5 times.

1:10 can be though as 1/10

So how do you get 1/10 from 1/5? Or how many 1/5 are there in 1/10?

Divide
(1/10) / (1/5)
=0.1 / 0.2
= 1/2

This would mean that you can get 1:10 from 1:5 culture by either
-using half the cells in 1:5 culture while keeping the volume constant
-using all the cells in the 1:5 culture and double the volume of the culture.

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u need to take 50% of ur 1:5 sample and dilute with 50% of diluent.
so u r diluting ur 1:5 sample - two fold - to get a 1:10 dilution.

dont worry abt calculations, i was never good at it and dont seem to b getting better even with time.
I am sure u r smarter than me to learn the these tricks.

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here are some tools to help:

this one from Promega (thanks, Fred!)

this one from Sigma

molar calculations

basic stats stuff

nother molarity calculator

some sequence manipulations

and my favorite link to some great tools and tips: www.protocol-online.org

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