[aeacfm]

I tried to determine CO2 in water according to the method in standard methods " titrimetric method for free Carbon dioxide " page 298... i used the pH electrode to detect  the end point @ 8.3
but .!!!!
every time i proceed in the titration  , when pH reached (8 ) suddenly it decreases and with adding huge amounts of the titrant bicarbonte no change occur and i cant reach the end point at ( 8.3) 

any help please
 

[MERCK86]

Hi
Do the titration faster and rapidly to reach the end point, CO2 can be absorbed to the solution, there are a few amounts of it in the air and it can be absorbed from your breathing too.