A New Thin-Layer Chromatographic System for the Identification and Selective Separation of Brilliant Blue Food Dye: Application of a Green Solvent

摘要

Silica gel and polyaniline-modified silica gel were used as stationary phases with aqueous methanol as the mobile phase for the comparative study of the migration behavior of dyes in order to select the most suitable thin-layer chromatographic system for the resolution of coexisting dyes. A better separation efficiency was observed by modifying silica gel with polyaniline as compared to pure silica static phase. Densitographic presentation of separations achieved on polyaniline-modified silica gel was also presented. The separation patterns of the dyes were also examined by replacing methanol with other alcohols. The thin-layer chromatographic system comprising of polyaniline-modified silica gel [(Pani-SG (EB1)] as the static phase and aqueous methanol (methanol-DDW, 1: 9) as the mobile phase was the most favorable for the selective separation of brilliant blue from tartrazine and carmoisine. Silica gel and the modified silica gel nanocomposite of the static phase have been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies were undertaken to characterize silica gel and modified silica gel (nanocomposite). Food dyes such as brilliant blue and tartrazine (in Ambrodil* S syrup) as well as carmoisine (in Flucold (TM) syrup) were successfully identified using the proposed thin-layer chromatographic method.