Study On Determination Of Four Basic Dyes In Foods By High Performance Liquid Chromatography

"Food Sanitation Law of the People's Republic of China" provides available food colorant types and using methods. After "the sudan event", the country has enforced punishments on unwarrantable use of sudan dyes. But for their own benefits, some producers divert their attention to other chemical dyes for food coloring. Chrysoidine G, Rhodamine B, Auramine O and Basic red are industrial dye but not food additives, which bring unsafety to food coloring, and are harmful to consumers'health.A method to determine Chrysoidine G, Rhodamine B and Auramine O simultaneously by high performance liquid chromatography(HPLC) was developed. The effects of mobile phase composition, proportion, concentration of ammonium acetate, column temperature, flow rate and injection volumn on separation have been studied. The best chromatographic conditions included a ZORBAX SB-C18 column (150 mm×4.6 mm,5μm) and a DAD detector. The optimal detection wavelengths were 410 nm,550nm and 435nm respectively. The column temperature was 30℃. The mobile phase were methanol and 0.015 mol/L ammonium acetate (85:15, v/v). The flow rate was 0.9 mL/min. The injection volume was 10μL. Under the optimal conditions, calibration curves of each component were established, and the correlation coefficients were all of 0.9999. The detection limits of Chrysoidine G, Rhodamine B and Auramine O were 0.05 mg/kg,0.02 mg/kg和0.1 mg/kg respectively. The recoveries of standard in samples were in the range of 80.5～104.5%, and RSD of the method was within 2.5%. The method has achieved the simultaneous determination of the three components in 4 minutes.A HPLC method for the determination of basic red in food was also proposed. Effects of the ratio of the mobile phase, pH value of the buffer solution, the column temperature, the flow rate, the injection volume and other factors on separation have been studied. The optimal conditions of chromatography included a C18 column (4.6 mmi.d.×150 mm,5μm) and a DAD detector at 520 nm. The column temperature was 30℃, using a mobile phase of methanol/ammonium acetate (2:98, v/v) at a flow rate of 0.9 mL/min. The injectinon volume was 2.0μL. Under the optimal conditions, the calibration curves were achieved. The linear scope ranged from 0.320μg/mL to 80.00μg/mL. The linear equation was y=184.34x+ 115.67 with the correlation coefficient r of 0.9990. The detection limit was 0.1 mg/kg. The RSD of basic red wasl.9%, and the average recovery of the samples was 97.4%. The method has been applied in the rapid determination of basic red.Results showed that the HPLC methods established for the determination of Chrysoidine G, Rhodamine B, Auramine O and basic red in food were simple, rapid, accurate and well reproducible with low detection limits.