[AlphaScent]

I am doing a titration on nBuLi using diphenylacetic acid and dry THF under a N2 atmosphere.  When the procedure says that towards the end of the titration the yellow color will take longer to go away.  But when one drop is added a persistent yellow color appears. 

My question is..how much time is persistent?  If I wait 10 min, 20 min, 1 hour ect??

Thank you for the responses!

[pgk]

Don’t worry about that.
At the end point of non-aqueous titrations, the color change often occurs slowly and sometimes the color change, turns back. Thus and as a general practice: when the color change gets persistent, the final titration volume is the consumed titrant volume minus one drop.