o-Cresolphthalein Complexone

o-Cresolphthalein Complexone is a pH indicator dye that is colorless at pH 8.2 and red at pH 9.8 and commonly used for the colorimetric determination of calcium. Spectral data: UV-Visible (λmax) 577-580 nm in 0.1 M NaOH. o-CPC is used for automated determination of calcium in serum and plasma, as well as in other biological fluids. o-CPC works by forming a complex with calcium ions in an alkaline solution. The complex is purple in color, and the intensity of the color is proportional to the concentration of calcium ions in the solution. This makes o-CPC a useful tool for measuring calcium levels in serum. o-CPC has also been used as an alkaline earth metal ion indicator and in the synthesis of some polymers. o-Cresolphthalein Complexone (o-CPC) is an indicator in complexometric titrations. Complexometric titrations involve the titration of metal ions with a chelating agent, and o-CPC is a post-column reagent (PCR) often used to detect the endpoint of the titration. In the presence of metal ions, particularly divalent metal ions such as calcium (Ca2+) and magnesium (Mg2+), o-CPC forms stable complexes with these ions. The color change of the complex is used to signal the endpoint of the titration. o-CPC is often used as analytic reagent for detection of trace chemicals (e.g. in water analysis).