Simultaneous Determination of Carmoisine and Ponceau 4R

A new, simple, sensitive, and inexpensive method for simultaneous determination of binary mixtures of food colorants, carmoisine and ponceau 4R, which are species with highly overlapped spectra, by using H-point standard addition method (HPSAM) is proposed. Absorbances at the two pair of wavelengths, 460 and 549 nm or 490 and 541 rim, were monitored while adding standard solutions of carmoisine or ponceau 4R, respectively. The accuracy and reproducibility of the determination method for various known amounts of carmoisine and ponceau 4R in their binary mixtures were evaluated. This method was satisfactorily applied for the determination of carmoisine and ponceau 4R in synthetic binary mixtures and several commercial products. The total relative standard error for applying the HPSAM to five synthetic samples was 3.26% or 4.96% with carmoisine or ponceau 4R addition, respectively.