Rosocyanine

Rosocyanine and Rubrocurcumin are two red colored materials, which are formed by the reaction between curcumin and borates.

Application

The color reaction between borates and curcumin is used within the spectrophotometrical determination and quantification of boron present in food or materials. Curcumin is a yellow coloring natural pigment found in the root stocks of some Curcuma species, especially Curcuma longa (turmeric), in concentrations up to 3%. In the so-called curcumin method for boron quantification it serves as reaction partner for boric acid. The reaction is very sensitive and so the smallest quantities of boron can be detected. The maximum absorbance at 540 nm for rosocyanine is used in this colorimetric method. The formation of rosocyanine depends on the reaction conditions. The reaction is carried out preferentially in acidic solutions containing hydrochloric or sulfuric acid. The color reaction also takes place under different conditions; however, in alkaline solution, gradual decomposition is observed. The reaction might be disturbed at higher pH values, interfering with other compounds.