DEVELOPMENT AND VALIDATION OF A TLC METHOD FOR THE ANALYSIS OF SYNTHETIC FOOD-STUFF DYES

Abstract

A novel reversed-phase thin-layer chromatographic (RP-TLC) method was developed for simultaneous determination of ten most commonly used artificial food dyes. The method was validated with respect to specificity, linearity, precision, and accuracy and compared with reversed-phase high performance liquid chromatography (RP-HPLC) method. In the case of TLC method horizontal developing technique was employed using octadecyl-modified silica as a stationary phase and 0.5 mol dm−3 ammonium sulfate in 30% of ethanol-water solution as a mobile phase. HPLC analysis was carried out using XDB-C18 column and gradient of mixture of aqueous ammonium acetate solution (0.1 mol dm−3, pH = 6.5) and MeOH/ACN (1:1, v/v). Colorants were detected at 450, 500, and 625 nm wavelengths. The TLC method proved to be suitable for quantitative determination in relatively wide range of concentrations (20–300 ng/band). Satisfactory values of limits of detection and quantitation were established for both techniques, although somewhat higher in the case of TLC, ranging from 2–10 ng/band, that is, 3–20 ng/band. Both methods can be applied with satisfactory precision and accuracy, with clear advantage of TLC for simultaneous analysis of six samples per hour.