Ponceau 4R azoic red dye

The synthetic red azo dye Ponceau 4R is an additive with widely utilization in food processing technology. Thermal behavior of the trisodium (8Z)-7-oxo-8-[(4-sulfonatonaphthalen-1-yl)hydrazinylidene] naphthalene-1,3-disulfonate, appointed Ponceau 4R or E124, was studied. Thermal analysis measurements of Ponceau 4R revealed thermal stability until 300 °C. Ponceau 4R is an anisotropic crystalline dye that has the property of birefringence. The THz spectroscopy allowed the determination of the characteristic absorption frequencies of this colorant and its identification in any food. In the THz spectrum of Ponceau 4R, it can be seen that the strongest absorption is produced for the radiation with frequency of 1.41, 1.74 and 3.81 THz. THz spectroscopy of Ponceau 4R identified spectral “signatures” of azo food dye studied, which were obtained by the processing of the numerical data of THz spectroscopy.