1% Phenolphthalein Solution in 91% Isopropanol (60 mL)
1% phenolphthalein indicator solution in a 91% isopropyl alcohol solvent. This solution was prepared using an A.C.S. Reagent. Shelf life of this product is one year and it is prepared monthly.
Phenolphthalein C20H14O4 is an organic compound used as an acid-base indicator. This compound dissolves poorly in water, and therefore it is typically prepared using alcohol as a solvent.
The indicator has a visual transition interval that is colorless at pH 8.0, pink at 8.5 and red at pH 10.0.
Phenolphthalein is commonly used as an indicator when titrating WVO (waste vegetable oil) for free fatty acid concentration.