Phenol Red Crystalline Reagent 99+% Purity Lab Grade

Phenol red is a sulfonephthalein pH indicator supplied as a crystalline lab grade reagent at 99+% purity in a 5 gram quantity. It changes from yellow through orange to red across roughly the pH 6.8 to 8.2 range, which places its transition close to physiological pH.

That range makes it the standard indicator in cell culture media, where color shift signals metabolic acidification, and it is also used in titrations, buffer checks, pool and aquarium test kits, and general laboratory pH work. The material is toxic and should be handled with the usual reagent precautions.