Definitely reuasable. The H2O2 is quite reactive and loses it's "trapping
capacity" rather quickly ie........don't save for another day.

"ab" > wrote in message
m...
> Hi,
>
> When doing determinations using a rankin, you add mixed indicator to
> the Hydrogen peroxide in the pear shaped flask. You then titrate until
> an end point is reached (ie the colour changes). You then perform the
> rest of the procedure and re-titrate back to the same end point to
> work out your SO2 levels.
>
> My question is once you have completed your determination, if wish to
> perform a second determination, do you need to change the indicator /
> hydrogen peroxide / NaOH solution in the pear flask?
>
> I wonder because you are starting from the same point (ie having
> titrated until an end point is found)...
>
> Any info would be appreciated
>
> AB1