# Making 0.2% acetic acid solution - (Jan/16/2008 )

Hi. I have a protocol that requires a 0.2% acetic acid solution to dissolve a compound. I have the glacial acetic acid reagent with me, but I'm not sure what to add to dilute it, and what proportions to dilute the glacial acetic acid to make the final solution. Can you please let me know how the solution is created, and how the volumes of each reagent added are calculated?

Thanks,
- Eli

-eli2k-

I have the glacial acetic acid reagent with me, but I'm not sure what to add to dilute it...

if not told otherwise in the protocol solutions are always made with aqua dest. but since i dont know what you want to do with this solution it could be something else. do you need the acetic acid solution for your living cells? in that case it could be PBS, HBSS or even medium.

...and what proportions to dilute the glacial acetic acid to make the final solution.

this is rather a problem of mathematics than cell biology.

percent can be either mL per mL or g per mL. most protocols are rather sloppy and wont tell you explicitly what sort of percent they are talking about! but lets assume its v/v cause glacial acid is a liquid.

glacial acid is per definition pure and waterfree. see if yours is labeled differently. like 95% acetic acid. but lets also assume its really 100% acetic acid.

0,2% are 2/1000 and thats 1/500. so you have basically 1 part acetic acid dissolved in 499 parts of water (or buffer or medium). thats the proportions.

Can you please let me know how the solution is created..

it depends. how much do you need? and how exactly has it to be 0,2%? if you dont want to add the acetic acid directly (like 20µL in 10mL) make it stepwise:
mix one part of glacial acetic acid with 4 parts of water. homogenize. mix one part of that with 9 parts of water. homogenize. again mix one part of that with 9 parts of water and homogenize again. there you have your 0,2%.
and if you need it for cell culture dont forget to filtrate or autoclave it.

-coastal-

Thank you. I think it's by pure volume (v/v it says on the protocol), so I just made 100ul in about 50ml of water, and filtered the solution to make it sterile.

-eli2k-