SCIENTIFIC STUDY & RESEARCH ♦ Vol. X (1) ♦ 2009 ♦ ISSN 1582-540X 73 THE LIQUID-CHROMATOGRAPHIC QUANTIFICATION OF SOME SYNTHETIC COLORANTS IN SOFT DRINKS Ion Trandafir *1 , Violeta Nour 2 , Mira Elena Ionică 2 1 University of Craiova, Faculty of Chemistry, Bd. Calea Bucuresti, no.107I, Craiova, Romania 2 University of Craiova, Faculty of Horticulture, Str. Al.I. Cuza no.13, Craiova, Romania *Corresponding author: nelutrandafir@yahoo.com Received: 17/03/2009 Accepted after revision: 06/04/2009 Abstract: A simple, selective, and precise reversed-phase HPLC method with "diode array" detection has been developed, enabling separation and quantification, in a single run of tartrazine (E 102), amaranth (E 123), erythrosine (E 127) and indigotine (E 132) in soft drinks. HPLC was performed with a Surveyor Thermo Electron system and the reversed phase chromatographic separation was achieved at 30 °C, using a DS Hypersil C18.5 μm column and a mobile phase made of 100 mM sodium acetate buffer and acetonitrile. Through optimization studies they were established: the gradient program of the elution, the injected volume 5 μL, the flow rate of the mobile phase 1mL/min, the duration of the analysis being 30 min. The synthetic colorants were detected by absorbance at λ = 430 nm for tartarzine, λ = 520 nm for amaranth and erythrosine and λ = 608 nm for indigotine. The method was validated in terms of sensitivity, linearity range, reproducibility, repeatability, analytical recovery and robustness. Keywords: tartrazine, amaranth, erythrosine, indigotine, HPLC, "diode array" detection, soft drinks