Simultaneous quantification of 13 synthetic food dyes in dietary supplements and sports nutrition by high-performance thin-layer chromatography with densitometric detection

In this study, a procedure was developed for the simultaneous quantification of 13 synthetic food dyes by high-performance thin-layer chromatography with densitometric detection in the wavelength range of 400–640 nm utilizing commercially-available silica HPTLC plates. As the development solvent, a mixture of ethyl acetate: acetonitrile: water: acetic acid in the ratio of 5.75: 6.25: 3.50: 1.00 (v/v) was used. The method detection and quantification limits were within the ranges of 1.0–5 and 2.5–10 ng/spot, respectively. The proposed method was validated and applied to the analysis of real samples, namely, power and vitamin drinks, and vitamin tablets, which were not labeled to contain synthetic dyes. The results were confirmed by high-performance liquid chromatography. Among the analyzed samples, two were found to contain synthetic dyes (tartrazine (E102) and brilliant blue FCF (E133)), however their concentrations were below the permitted levels. HPTLC was shown to be a promising screening technique for the synthetic dyes with the advantages of simplicity, high analysis speed, and low organic solvent consumption.