Simultaneous determination of synthetic edible pigments in beverages by titania-based RP-HPLC

A rapid method for simultaneous determination of five synthetic edible pigments (SEPs) including tartrazine (TA), ponceau 4R (PO), sunset yellow (SY), brilliant blue (BB) and erythrosine (ER) in beverages with titania-based RP-HPLC has been developed. The good linear relationships were obtained in the concentration ranges of 2.5–40 μg mL−1 for TA, PO and SY, 0.75–12 μg mL−1 for BB, and 1.25–20 μg mL−1 for ER, respectively. The detection limits (LODs) of five SEPs were 0.042, 0.021, 0.042, 0.0005, and 0.021 μg mL−1, respectively. The average recoveries were between 92.2% and 106.3%. Relative standard deviations (RSD, n = 7) for five SEPs were less than 1.18%. The precision and accuracy of the method can meet the requirements of HPLC analysis. In addition, the thermodynamic parameters of retention of the pigments in the titania column such as enthalpy (ΔHο), entropy (ΔSο) and Gibbs free energy (ΔGο) were also determined. Keywords: Titania-based stationary phase, RP-HPLC, Synthetic edible pigments (SEPs), Beverages