Physical and Chemical Properties | Physicochemical properties Xylenol Orange is a kind of triphenylmethane chromogenic reagent. Scientific name "3,3 '-bis (N,N-dicarboxymethylaminomethyl)-O-cresenesulfonphthalein". Molecular formula C31H32N2O13S. Molecular weight 672.66. Reddish brown shiny crystalline powder. Easily deliquescent. Its sodium salt is soluble in water, but insoluble in alcohol and ether. Because of the structure of O-cresolphthalein, the pH value of the solution has a great influence on the color change. When pH>6.3, the solution shows red, and when pH<6.3, it shows yellow. With the majority of metal ions can form red-purple complexes. Therefore, when used as a metal indicator for Complexometric titration, it is suitable for acidic solutions with pH<6. Used for the determination of bismuth, thorium, scandium, lead, zinc, lanthanum, cadmium and mercury and other metal ions. Reagent is often prepared into 0.5% aqueous solution, the nature is more stable, can be maintained for 2~3 weeks. In addition, it can also be used as a chromogenic reagent for colorimetric analysis, for example, in hydrochloric acid medium, and niobium forms an orange complex, and the maximum absorption wavelength is about 520~530 nm, the maximum absorption wavelength of the reagent is about 434~460 nm, which is used for the determination of trace niobium in ore samples and steel. |