O-Cresolphthalein

O-Cresolphthalein (CAS 596-27-0) is a phthalein-type pH indicator and metal ion chelating agent widely used in analytical and clinical chemistry. It belongs to the family of phenolphthalein derivatives, distinguished by two ortho-cresol substituents that enhance its sensitivity to calcium and magnesium ions.
In its free acid form, O-Cresolphthalein appears as a white crystalline powder. In alkaline solution (pH 8.2–9.8), it transitions from colorless to a vivid red-purple, making it an excellent visual indicator for acid-base titrations and calcium detection in biological fluids.
O-Cresolphthalein Complexone (also known as O-Cresolphthalein Complexon or OCPC) is its chelating derivative, widely adopted in clinical chemistry analyzers for automated serum calcium determination. This form is one of the most globally standardized reagents for calcium measurement in hospital laboratories.
Runtai Chemical is a professional and reliable China manufacturer of O-Cresolphthalein with CAS 596-27-0 with higher purity and lower price. If you are interested in our O-Cresolphthalein, PLS free to contact us for a free sample!