Newsha Mahmoodi - Department of Food Science and Technology, Faculty of Science and innovative technology, Islamic Azad University of Pharmaceutical Sciences, Tehran, Iran.
Mohammad Faraji - Faculty of Food Industry and Agriculture, Department of Food science & Technology, Standard Research Institute (SRI), Karaj P.O. Box 31745-139, Iran.
Parisa ziarati - Department of Medicinal Chemistry, Faculty of Pharmacy, Pharmaceutical Sciences Branch , Islamic Azad University, Tehran – Iran (IAUPS)

An efficient method was developed for the simultaneous determination of sunset yellow and carmoisine in soft drink samples by high performance liquid chromatography (HPLC-UV-Vis). Affecting parameters on separation and detection of the dyes were investigated and optimized.Mixture of acetate buffer pH=6.7 and acetonitrile with ratio 78:22 as mobile phase; flow rate 1.0 ml/min and detection wavelength of 500 nm were selected as optimum values. For these dyes goodlinearity (0.25–50 mg L-1, > r2=0.99) were obtained. Limits of detection for both of the dyes were 0.1 mg L-1. The recoveries of the dyes ranged from 90.4 to 109.2%. Intra and inter-day precision expressed as relative standard deviation (RSD%) at 5.0 and 50 mg L-1 levels less than 8.0% were alsoachieved. This method has been applied successfully in the determination of the dyes in soft drink samples. Sunset yellow and carmoisine were found in the samples in the range of 10.3-42.1 and N.D- 4.5 mg L-1, respectively. Obtained results showed that levels of the sunset yellow individually or incombination with carmoisine in all of the tested samples is lower than EU maximum permitted level (100 mg L-1).

Carmoisine, HPLC-UV/Vis, Orange flavored soft drinks, Sunset yellow, Synthetic dyes