摘要：The separation and detection of some natural dyes comprising 12 water soluble and 8 non-water soluble dyes were investigated by thin-layer chromatography by using polyamide as an adsorbent. Polyamide 11 F254 layers and polyamide layer sheets were used as plates, two series of water and nonwater soluble dyes being developed with different solvent systems, respectively. The solvent systems for the separation of non-water soluble dyes were n-hexane, n-hexane-benzene-acetic acid (6 : 3 : 1) and acetone-acetic acid (19 : 1). Especially the development with n-hexane was most suitable for the separation of β-carotene from paprika extract. When developed with isopropanol-formic acid-water (7 : 1 : 3), all water soluble dyes were separated. In the development, dyes containing anthocyanin derivatives such as grape skin and purple corn extracts were observed as slightly overlapped spots, showing that the dyes were composed of many compounds.
