[lingo_belle]

Hi all,

I'm doing COD determination with potassium permanganate. I do know that it's not a stable titrant thus I standardized it with sodium oxalate. May I know if it's necessary for me to do so every time before I start the titrations? Can I standardized it once, and use the stock for every titrations? How abt if it was to left overnight? Will it affect the freshness of the stock?

Thanks all

belle

[Borek]

If you have defined operating procedure - stick to it. If you don't - keep the solution in the dark bottle in the dark place. Standarization on the daily basis doesn't make sense, either once a week or once a month will be enough. Try by yourself - for the first month do it every week, you will have good idea about the solution stability.