• One drop of phenolphthalein indicator may be used to help determine whether the potentiometric titration is complete, as indicated by the phenolphthalein color change from colorless to pink. This is especially helpful where the titration proceeds through two inflections. Note, however, that the potentiometric endpoint may occur slightly after the phenolphthalein color change is observed. Also, care must be taken that the amount of phenolphthalein added is minimal. If more than one drop is added, a false high endpoint may result.