Fluorospectrophotometric Determination of Sudan Red in Food

In a 1.0×10-3mol·L H2SO4 medium, sensitization effect of Cerium(Ⅳ) sulfate on the fluorescence of Sudan red was observed obviously. The magnitude of increase in fluorescence intensity was found to keep linear relationship with the mass concentration of the colorants in ranges of 0.20-14.9 mg·L-1 (for Sundan redⅠ), 0.10-11.1 mg·L-1 (for Sundan redⅡ), 0.20-10.6 mg·L-1 (for Sundan red Ⅲ) and 0.20-11.4 mg·L-1 (for Sundan red Ⅳ), as measured at the wavelength of 362 nm (λex). Detection limits (3s/k) of the method were found to be 4.0, 3.6, 4.2 and 4.2 mg·L-1 respectively. The proposed method was applied to the analysis of sauce samples of tomato and chili, giving values of recovery in the range of 98.1%-104% with RSD′s (n=5) in the range of 3.0%-6.5%.